[libpng16] Imported from libpng-1.6.15.tar

[libpng16] Imported from libpng-1.6.15rc03.tar
[libpng16] Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in
2025-07-10 18:04:09 +02:00 · 2014-11-20 10:22:57 -06:00 · 2014-11-16 20:04:53 -06:00 · 2014-11-16 19:37:42 -06:00 · 2014-11-14 17:59:40 -06:00 · 2014-11-14 09:51:59 -06:00
132 changed files with 6682 additions and 3863 deletions
--- a/89
+++ b/89
@@ -1,64 +1,61 @@
+Libpng 1.6.15 - November 20, 2014

-Libpng 1.6.9beta02 - January 1, 2014
-
-This is not intended to be a public release.  It will be replaced
-within a few weeks by a public version or by another test version.
+This is a public release of libpng, intended for use in production codes.

 Files available for download:

 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script

-   1.6.9beta02.tar.xz (LZMA-compressed, recommended)
-   1.6.9beta02.tar.gz
+   libpng-1.6.15.tar.xz (LZMA-compressed, recommended)
+   libpng-1.6.15.tar.gz

 Source files with CRLF line endings (for Windows), without the
 "configure" script

-   lp169b02.7z  (LZMA-compressed, recommended)
-   lp169b02.zip
+   lpng1615.7z  (LZMA-compressed, recommended)
+   lpng1615.zip

 Other information:

-   1.6.9beta02-README.txt
-   1.6.9beta02-LICENSE.txt
-   Gnupg/*.asc (PGP armored detached signatures)
+   libpng-1.6.15-README.txt
+   libpng-1.6.15-LICENSE.txt
+   libpng-1.6.15-*.asc (armored detached GPG signatures)

-Changes since the last public release (1.6.8):
-
-Version 1.6.9beta01 [December 26, 2013]
-  Bookkeeping: Moved functions around (no changes). Moved transform
-    function definitions before the place where they are called so that
-    they can be masde static. Move the intrapixel functions and the
-    grayscale palette builder out of the png?tran.c files. The latter
-    isn't a transform function and is no longer used internally, and the
-    former MNG specific functions are better placed in pngread/pngwrite.c
-  Made transform implementation functions static. This makes the internal
-    functions called by png_do_{read|write}_transformations static. On an
-    x86-64 DLL build (Gentoo Linux) this reduces the size of the text
-    segment of the DLL by 1208 bytes, about 0.6%. It also simplifies
-    maintenance by removing the declarations from pngpriv.h and allowing
-    easier changes to the internal interfaces.
-  Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69
-    in the tar distributions.
-
-Version 1.6.9beta02 [January 1, 2014]
-  Added checks for libpng 1.5 to pngvalid.c.  This supports the use of
-    this version of pngvalid in libpng 1.5
-  Merged with pngvalid.c from libpng-1.7 changes to create a single
-    pngvalid.c
-  Removed #error macro from contrib/tools/pngfix.c (Thomas Klausner).
-  Merged pngrio.c, pngtrans.c, pngwio.c, and pngerror.c with libpng-1.7.0
-  Merged libpng-1.7.0 changes to make no-interlace configurations work
-    with test programs.
-  Revised pngvalid.c to support libpng 1.5, which does not support the
-    PNG_MAXIMUM_INFLATE_WINDOW option, so #define it out when appropriate in
-    pngvalid.c
-  Allow unversioned links created on install to be disabled in configure.
-    In configure builds 'make install' changes/adds links like png.h
-    and libpng.a to point to the newly installed, versioned, files (e.g.
-    libpng17/png.h and libpng17.a). Three new configure options and some
-    rearrangement of Makefile.am allow creation of these links to be disabled.
+Changes since the last public release (1.6.14):
+  Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+  Simplified png_free_data().
+  Added missing "ptr = NULL" after some instances of png_free().
+  Made a one-line revision to configure.ac to support ARM on aarch64
+    (bug report by Marcin Juszkiewicz, fix by John Bowler).
+  Avoid out-of-bounds memory access in png_user_version_check().
+  Simplified and future-proofed png_user_version_check().
+  Fixed GCC unsigned int->float warnings. Various versions of GCC
+    seem to generate warnings when an unsigned value is implicitly
+    converted to double. This is probably a GCC bug but this change
+    avoids the issue by explicitly converting to (int) where safe.
+  Free all allocated memory in pngimage. The file buffer cache was left
+    allocated at the end of the program, harmless but it causes memory
+    leak reports from clang.
+  Fixed array size calculations to avoid warnings. At various points
+    in the code the number of elements in an array is calculated using
+    sizeof.  This generates a compile time constant of type (size_t) which
+    is then typically assigned to an (unsigned int) or (int). Some versions
+    of GCC on 64-bit systems warn about the apparent narrowing, even though
+    the same compiler does apparently generate the correct, in-range,
+    numeric constant.  This adds appropriate, safe, casts to make the
+    warnings go away.
+  Removed #ifdef PNG_16BIT_SUPPORTED/#endif around png_product2(); it is
+    needed by png_reciprocal2().
+  Added #ifdef PNG_16BIT_SUPPORTED/#endif around png_log16bit() and
+    png_do_swap().
+  Changed all "#endif /* PNG_FEATURE_SUPPORTED */" to "#endif /* FEATURE */"
+  The macros passed in the command line to Borland make were ignored if
+    similarly-named macros were already defined in makefiles. This behavior
+    is different from POSIX make and other make programs.  Surround the
+    macro definitions with ifndef guards (Cosmin).
+  Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in scripts/makefile.vcwin32.
+  Removed the obsolete $ARCH variable from scripts/makefile.darwin.

 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
--- a/324
+++ b/324
@@ -1,4 +1,4 @@
-#if 0
+
 CHANGES - changes for libpng

 Version 0.2
@@ -4345,8 +4345,9 @@ Version 1.6.0beta37 [January 10, 2013]
    programs to generate and test a PNG which should have the problem.

 Version 1.6.0beta39 [January 19, 2013]
-  Again corrected attempt at overflow detection in png_set_unknown_chunks().
-  Added overflow detection in png_set_sPLT() and png_set_text_2().
+  Again corrected attempt at overflow detection in png_set_unknown_chunks()
+  (CVE-2013-7353).  Added overflow detection in png_set_sPLT() and
+  png_set_text_2() (CVE-2013-7354).

 Version 1.6.0beta40 [January 20, 2013]
  Use consistent handling of overflows in text, sPLT and unknown png_set_* APIs
@@ -4429,7 +4430,7 @@ Version 1.6.1beta05 [March 1, 2013]
 Version 1.6.1beta06 [March 4, 2013]
  Better documentation of unknown handling API interactions.
  Corrected Android builds and corrected libpng.vers with symbol
-    prefixing This adds an API to set optimization options externally,
+    prefixing. This adds an API to set optimization options externally,
    providing an alternative and general solution for the non-portable
    run-time tests used by the ARM Neon code.  It also makes those tests
    compile and link on Android.
@@ -4754,7 +4755,7 @@ Version 1.6.8 [December 19, 2013]
 Version 1.6.9beta01 [December 26, 2013]
  Bookkeeping: Moved functions around (no changes). Moved transform
    function definitions before the place where they are called so that
-    they can be masde static. Move the intrapixel functions and the
+    they can be made static. Move the intrapixel functions and the
    grayscale palette builder out of the png?tran.c files. The latter
    isn't a transform function and is no longer used internally, and the
    former MNG specific functions are better placed in pngread/pngwrite.c
@@ -4785,6 +4786,318 @@ Version 1.6.9beta02 [January 1, 2014]
    libpng17/png.h and libpng17.a). Three new configure options and some
    rearrangement of Makefile.am allow creation of these links to be disabled.

+Version 1.6.9beta03 [January 10, 2014]
+  Removed potentially misleading warning from png_check_IHDR().
+
+Version 1.6.9beta04 [January 20, 2014]
+  Updated scripts/makefile.* to use CPPFLAGS (Cosmin).
+  Added clang attribute support (Cosmin).
+
+Version 1.6.9rc01 [January 28, 2014]
+  No changes.
+
+Version 1.6.9rc02 [January 30, 2014]
+  Quiet an uninitialized memory warning from VC2013 in png_get_png().
+
+Version 1.6.9 [February 6, 2014]
+
+Version 1.6.10beta01 [February 9, 2014]
+  Backported changes from libpng-1.7.0beta30 and beta31:
+  Fixed a large number of instances where PNGCBAPI was omitted from
+    function definitions.
+  Added pngimage test program for png_read_png() and png_write_png()
+    with two new test scripts.
+  Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling
+    png_set_packing() in png_read_png().
+  Fixed combination of ~alpha with shift. On read invert alpha, processing
+    occurred after shift processing, which causes the final values to be
+    outside the range that should be produced by the shift. Reversing the
+    order on read makes the two transforms work together correctly and mirrors
+    the order used on write.
+  Do not read invalid sBIT chunks. Previously libpng only checked sBIT
+    values on write, so a malicious PNG writer could therefore cause
+    the read code to return an invalid sBIT chunk, which might lead to
+    application errors or crashes.  Such chunks are now skipped (with
+    chunk_benign_error).
+  Make png_read_png() and png_write_png() prototypes in png.h depend
+    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
+  Support builds with unsupported PNG_TRANSFORM_* values.  All of the
+    PNG_TRANSFORM_* values are always defined in png.h and, because they
+    are used for both read and write in some cases, it is not reliable
+    to #if out ones that are totally unsupported. This change adds error
+    detection in png_read_image() and png_write_image() to do a
+    png_app_error() if the app requests something that cannot be done
+    and it adds corresponding code to pngimage.c to handle such options
+    by not attempting to test them.
+
+Version 1.6.10beta02 [February 23, 2014]
+  Moved redefines of png_error(), png_warning(), png_chunk_error(),
+    and png_chunk_warning() from pngpriv.h to png.h to make them visible
+    to libpng-calling applications.
+  Moved OS dependent code from arm/arm_init.c, to allow the included
+    implementation of the ARM NEON discovery function to be set at
+    build-time and provide sample implementations from the current code in the
+    contrib/arm-neon subdirectory. The __linux__ code has also been changed to
+    compile and link on Android by using /proc/cpuinfo, and the old linux code
+    is in contrib/arm-neon/linux-auxv.c.  The new code avoids POSIX and Linux
+    dependencies apart from opening /proc/cpuinfo and is C90 compliant.
+  Check for info_ptr == NULL early in png_read_end() so we don't need to
+    run all the png_handle_*() and depend on them to return if info_ptr == NULL.
+    This improves the performance of png_read_end(png_ptr, NULL) and makes
+    it more robust against future programming errors.
+  Check for __has_extension before using it in pngconf.h, to
+    support older Clang versions (Jeremy Sequoia).
+  Treat CRC error handling with png_set_crc_action(), instead of with
+    png_set_benign_errors(), which has been the case since libpng-1.6.0beta18.
+  Use a user warning handler in contrib/gregbook/readpng2.c instead of default,
+    so warnings will be put on stderr even if libpng has CONSOLE_IO disabled.
+  Added png_ptr->process_mode = PNG_READ_IDAT_MODE in png_push_read_chunk
+    after recognizing the IDAT chunk, which avoids an infinite loop while
+    reading a datastream whose first IDAT chunk is of zero-length.
+    This fixes CERT VU#684412 and CVE-2014-0333.
+  Don't recognize known sRGB profiles as sRGB if they have been hacked,
+    but don't reject them and don't issue a copyright violation warning.
+
+Version 1.6.10beta03 [February 25, 2014]
+  Moved some documentation from png.h to libpng.3 and libpng-manual.txt
+  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
+
+Version 1.6.10rc01 [February 27, 2014]
+  Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS
+    and PNG_USR_CONFIG -> PNG_USER_CONFIG).
+
+Version 1.6.10rc02 [February 28, 2014]
+  Removed unreachable return statement after png_chunk_error()
+    in pngrutil.c
+
+Version 1.6.10rc03 [March 4, 2014]
+  Un-deprecated png_data_freer().
+
+Version 1.6.10 [March 6, 2014]
+  No changes.
+
+Version 1.6.11beta01 [March 17, 2014]
+  Use "if (value != 0)" instead of "if (value)" consistently.
+  Changed ZlibSrcDir from 1.2.5 to 1.2.8 in projects/vstudio.
+  Moved configuration information from the manual to the INSTALL file.
+
+Version 1.6.11beta02 [April 6, 2014]
+  Removed #if/#else/#endif from inside two pow() calls in pngvalid.c because
+    they were handled improperly by Portland Group's PGI-14.1 - PGI-14.3
+    when using its "__builtin_pow()" function.
+  Silence 'unused parameter' build warnings (Cosmin Truta).
+  $(CP) is now used alongside $(RM_F).  Also, use 'copy' instead of 'cp'
+    where applicable, and applied other minor makefile changes (Cosmin).
+  Don't warn about invalid dimensions exceeding user limits (Cosmin).
+  Allow an easy replacement of the default pre-built configuration
+    header with a custom header, via the make PNGLIBCONF_H_PREBUILT
+    macro (Cosmin).
+
+Version 1.6.11beta03 [April 6, 2014]
+  Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes
+    with "blocky" expansion of sub-8-bit interlaced PNG files (Eric Huss).
+  Optionally use  __builtin_bswap16() in png_do_swap().
+
+Version 1.6.11beta04 [April 19, 2014]
+  Made progressive reading of interlaced images consistent with the
+    behavior of the sequential reader and consistent with the manual, by
+    moving some code out of the PNG_READ_INTERLACING_SUPPORTED blocks. The
+    row_callback now receives the proper pass number and unexpanded rows, when
+    png_combine_row() isn't built or used, and png_set_interlace_handling()
+    is not called.
+  Allow PNG_sRGB_PROFILE_CHECKING = (-1) to mean no sRGB profile checking.
+
+Version 1.6.11beta05 [April 26, 2014]
+  Do not reject ICC V2 profiles that lack padding (Kai-Uwe Behrmann).
+  Relocated closing bracket of the sRGB profile test loop to avoid getting
+    "Not recognizing known sRGB profile that has been edited" warning for
+    ICC V2 profiles that lack the MD5 signature in the profile header.
+
+Version 1.6.11beta06 [May 19, 2014]
+  Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option().
+
+Version 1.6.11rc01 [May 27, 2014]
+  No changes.
+
+Version 1.6.11rc02 [June 3, 2014]
+  Test ZLIB_VERNUM instead of PNG_ZLIB_VERNUM in contrib/tools/pngfix.c
+
+Version 1.6.11 [June 5, 2014]
+  No changes.
+
+Version 1.6.12rc01 [June 6, 2014]
+  Relocated new code from 1.6.11beta06 in png.c to a point after the
+    declarations (Max Stepin).
+
+Version 1.6.12rc02 [June 7, 2014]
+  Changed file permissions of contrib/tools/intgamma.sh,
+    test-driver, and compile from 0644 to 0755 (Cosmin).
+
+Version 1.6.12rc03 [June 8, 2014]
+  Ensure "__has_attribute()" macro exists before trying to use it with
+    old clang compilers (MacPorts Ticket #43939).
+
+Version 1.6.12 [June 12, 2014]
+  No changes.
+
+Version 1.6.13beta01 [July 4, 2014]
+  Quieted -Wsign-compare and -Wclobber compiler warnings in
+    contrib/pngminus/*.c
+  Added "(void) png_ptr;" where needed in contrib/gregbook to quiet
+    compiler complaints about unused pointers.
+  Split a long output string in contrib/gregbook/rpng2-x.c.
+  Added "PNG_SET_OPTION" requirement for sRGB chunk support to pnglibconf.dfa,
+    Needed for write-only support (John Bowler).
+  Changed "if defined(__ARM_NEON__)" to
+    "if (defined(__ARM_NEON__) || defined(__ARM_NEON))" (James Wu).
+  Fixed clang no-warning builds: png_digit was defined but never used.
+    
+Version 1.6.13beta02 [July 21, 2014]
+  Fixed an incorrect separator ("/" should be "\") in scripts/makefile.vcwin32
+    (bug report from Wolfgang S. Kechel).  Bug was introduced in libpng-1.6.11.
+    Also fixed makefile.bc32, makefile.bor, makefile.msc, makefile.intel, and
+    makefile.tc3 similarly.
+
+Version 1.6.13beta03 [August 3, 2014]
+  Removed scripts/makefile.elf. It has not worked since libpng-1.5.0beta14
+    due to elimination of the PNG_FUNCTION_EXPORT and PNG_DATA_EXPORT
+    definitions from pngconf.h.
+  Ensure that CMakeLists.txt makes the target "lib" directory before making
+    symbolic link into it (SourceForge bug report #226 by Rolf Timmermans).
+
+Version 1.6.13beta04 [August 8, 2014]
+  Added opinion that the ECCN (Export Control Classification Number) for
+    libpng is EAR99 to the README file.
+  Eliminated use of "$<" in makefile explicit rules, when copying
+    $PNGLIBCONF_H_PREBUILT.  This does not work on some versions of make;
+    bug introduced in libpng version 1.6.11.
+
+Version 1.6.13rc01 [August 14, 2014]
+  Made "ccopts" agree with "CFLAGS" in scripts/makefile.hp* and makefile.*sunu
+
+Version 1.6.13 [August 21, 2014]
+  No changes.
+
+Version 1.6.14beta01 [September 14, 2014]
+  Guard usage of png_ptr->options with #ifdef PNG_SET_OPTION_SUPPORTED.
+  Do not build contrib/tools/pngfix.c when PNG_SETJMP_NOT_SUPPORTED,
+    to allow "make" to complete without setjmp support (bug report by
+    Claudio Fontana)
+  Add "#include <setjmp.h>" to contrib/tools/pngfix.c (John Bowler)
+
+Version 1.6.14beta02 [September 18, 2014]
+  Use nanosleep() instead of usleep() in contrib/gregbook/rpng2-x.c
+    because usleep() is deprecated.
+  Define usleep() in contrib/gregbook/rpng2-x.c if not already defined
+    in unistd.h and nanosleep() is not available; fixes error introduced
+    in libpng-1.6.13.
+  Disable floating point exception handling in pngvalid.c when
+    PNG_FLOATING_ARITHMETIC is not supported (bug report by "zootus
+    at users.sourceforge.net").
+
+Version 1.6.14beta03 [September 19, 2014]
+  Define FE_DIVBYZERO, FE_INVALID, and FE_OVERFLOW in pngvalid.c if not
+    already defined.  Revert floating point exception handling in pngvalid.c
+    to version 1.6.14beta01 behavior.
+
+Version 1.6.14beta04 [September 27, 2014]
+  Fixed incorrect handling of the iTXt compression flag in pngrutil.c
+    (bug report by Shunsaku Hirata).  Bug was introduced in libpng-1.6.0.
+
+Version 1.6.14beta05 [October 1, 2014]
+  Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
+
+Version 1.6.14beta06 [October 5, 2014]
+  Removed unused "text_len" parameter from private function png_write_zTXt().
+  Conditionally compile some code in png_deflate_claim(), when
+    PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.
+  Replaced repeated code in pngpread.c with PNG_PUSH_SAVE_BUFFER_IF_FULL.
+  Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT"
+    to pnglibconf.dfa.
+  Removed "option READ_COMPRESSED_TEXT enables READ_TEXT" from pnglibconf.dfa,
+    to make it possible to configure a libpng that supports iCCP but not TEXT.
+
+Version 1.6.14beta07 [October 7, 2014]
+  Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
+  Only mark text chunks as written after successfully writing them.
+
+Version 1.6.14rc01 [October 15, 2014]
+  Fixed some typos in comments.
+
+Version 1.6.14rc02 [October 17, 2014]
+  Changed png_convert_to_rfc_1123() to png_convert_to_rfc_1123_buffer()
+    in the manual, to reflect the change made in libpng-1.6.0.
+  Updated README file to explain that direct access to the png_struct
+    and info_struct members has not been permitted since libpng-1.5.0.
+
+Version 1.6.14 [October 23, 2014]
+  No changes.
+
+Version 1.6.15beta01 [October 29, 2014]
+  Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+  Simplified png_free_data().
+  Added missing "ptr = NULL" after some instances of png_free().
+
+Version 1.6.15beta02 [November 1, 2014]
+  Changed remaining "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+
+Version 1.6.15beta03 [November 3, 2014]
+  Added PNG_USE_ARM_NEON configuration flag (Marcin Juszkiewicz).
+
+Version 1.6.15beta04 [November 4, 2014]
+  Removed new PNG_USE_ARM_NEON configuration flag and made a one-line
+    revision to configure.ac to support ARM on aarch64 instead (John Bowler).
+
+Version 1.6.15beta05 [November 5, 2014]
+  Use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING in
+    example.c, pngtest.c, and applications in the contrib directory.
+  Avoid out-of-bounds memory access in png_user_version_check().
+  Simplified and future-proofed png_user_version_check().
+  Fixed GCC unsigned int->float warnings. Various versions of GCC
+    seem to generate warnings when an unsigned value is implicitly
+    converted to double. This is probably a GCC bug but this change
+    avoids the issue by explicitly converting to (int) where safe.
+  Free all allocated memory in pngimage. The file buffer cache was left
+    allocated at the end of the program, harmless but it causes memory
+    leak reports from clang.
+  Fixed array size calculations to avoid warnings. At various points
+    in the code the number of elements in an array is calculated using
+    sizeof.  This generates a compile time constant of type (size_t) which
+    is then typically assigned to an (unsigned int) or (int). Some versions
+    of GCC on 64-bit systems warn about the apparent narrowing, even though
+    the same compiler does apparently generate the correct, in-range,
+    numeric constant.  This adds appropriate, safe, casts to make the
+    warnings go away.
+
+Version 1.6.15beta06 [November 6, 2014]
+  Reverted use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING
+    in the manual, example.c, pngtest.c, and applications in the contrib
+    directory.  It was incorrect advice.
+
+Version 1.6.15beta07 [November 7, 2014]
+  Removed #ifdef PNG_16BIT_SUPPORTED/#endif around png_product2(); it is
+    needed by png_reciprocal2().
+  Added #ifdef PNG_16BIT_SUPPORTED/#endif around png_log16bit() and
+    png_do_swap().
+  Changed all "#endif /* PNG_FEATURE_SUPPORTED */" to "#endif /* FEATURE */"
+
+Version 1.6.15beta08 [November 8, 2014]
+  More housecleaning in *.h
+
+Version 1.6.15rc01 [November 13, 2014]
+
+Version 1.6.15rc02 [November 14, 2014]
+  The macros passed in the command line to Borland make were ignored if
+    similarly-named macros were already defined in makefiles. This behavior
+    is different from POSIX make and other make programs.  Surround the
+    macro definitions with ifndef guards (Cosmin).
+
+Version 1.6.15rc03 [November 16, 2014]
+  Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in scripts/makefile.vcwin32.
+  Removed the obsolete $ARCH variable from scripts/makefile.darwin.
+
+Version 1.6.15 [November 20, 2014]
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
@@ -4792,4 +5105,3 @@ to subscribe)
 or to glennrp at users.sourceforge.net

 Glenn R-P
-#endif
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 # CMakeLists.txt

-# Copyright (C) 2007-2013 Glenn Randers-Pehrson
+# Copyright (C) 2007-2014 Glenn Randers-Pehrson

 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -16,7 +16,7 @@ enable_testing()

 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 6)
-set(PNGLIB_RELEASE 9)
+set(PNGLIB_RELEASE 15)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

@@ -220,6 +220,7 @@ macro(CREATE_SYMLINK SRC_FILE DEST_FILE)
    ADD_CUSTOM_TARGET(${DEST_FILE}_COPY ALL DEPENDS ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
  else(WIN32 AND NOT CYGWIN AND NOT MSYS)
    get_filename_component(LINK_TARGET "${SRC_FILE}" NAME)
+    execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_LIBRARY_OUTPUT_DIRECTORY})
    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
  endif(WIN32 AND NOT CYGWIN AND NOT MSYS)
@@ -252,7 +253,7 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#   VERSION 16.${PNGLIB_RELEASE}.1.6.9beta02
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.15
    VERSION 16.${PNGLIB_RELEASE}.0
    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
@@ -350,7 +351,7 @@ if(PNG_EXPORT_RULE AND NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL )
  install(EXPORT libpng DESTINATION lib/libpng FILE lib${PNG_LIB_NAME}.cmake)
 endif()

-# what's with libpng-$VER%.txt and all the extra files?
+# what's with libpng-manual.txt and all the extra files?

 # UNINSTALL
 # do we need this?
--- a/278
+++ b/278
@@ -1,13 +1,47 @@

 Installing libpng

+Contents
+
+   I. Simple installation
+  II. Rebuilding the configure scripts
+ III. Using scripts/makefile*
+  IV. Using cmake
+   V. Directory structure
+  VI. Building with project files
+ VII. Building with makefiles
+VIII. Configuring libpng for 16-bit platforms
+  IX. Configuring for DOS
+   X. Configuring for Medium Model
+  XI. Prepending a prefix to exported symbols
+ XII. Configuring for compiler xxx:
+XIII. Removing unwanted object code
+ XIV. Changes to the build and configuration of libpng in libpng-1.5.x
+  XV. Configuring libpng for multiprocessing
+ XVI. Other sources of information about libpng
+
+I. Simple installation
+
 On Unix/Linux and similar systems, you can simply type

    ./configure [--prefix=/path]
    make check
    make install

-and ignore the rest of this document.
+and ignore the rest of this document.  "/path" is the path to the directory
+where you want to install the libpng "lib", "include", and "bin"
+subdirectories.
+
+If you downloaded a GIT clone, you will need to run ./autogen.sh before
+running ./configure, to create "configure" and "Makefile.in" which are
+not included in the GIT repository.
+
+Note that "configure" is only included in the "*.tar" distributions and not
+in the "*.zip" or "*.7z" distributions. If you downloaded one of those
+distributions, see "Building with project files" or "Building with makefiles",
+below.
+
+II. Rebuilding the configure scripts

 If configure does not work on your system, or if you have a need to
 change configure.ac or Makefile.am, and you have a reasonably
@@ -24,9 +58,12 @@ aren't using any of the included pre-built scripts, you can do this:
    make install
    make check

+III. Using scripts/makefile*
+
 Instead, you can use one of the custom-built makefiles in the
 "scripts" directory

+    cp scripts/pnglibconf.h.prebuilt pnglibconf.h
    cp scripts/makefile.system makefile
    make test
    make install
@@ -38,8 +75,8 @@ Or you can use one of the "projects" in the "projects" directory.

 Before installing libpng, you must first install zlib, if it
 is not already on your system.  zlib can usually be found
-wherever you got libpng.  zlib can be placed in another directory,
-at the same level as libpng.
+wherever you got libpng; otherwise go to http://zlib.net.  You can place
+zlib in in the same directory as libpng or in another directory.

 If your system already has a preinstalled zlib you will still need
 to have access to the zlib.h and zconf.h include files that
@@ -59,15 +96,23 @@ LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
 If you are using one of the makefile scripts, put ZLIBLIB and ZLIBINC
 in your environment and type "make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test".

+IV. Using cmake
+
 If you want to use "cmake" (see www.cmake.org), type

   cmake . -DCMAKE_INSTALL_PREFIX=/path
   make
   make install

+As when using the simple configure method described above, "/path" points to
+the installation directory where you want to put the libpng "lib", "include",
+and "bin" subdirectories.
+
+V. Directory structure
+
 You can rename the directories that you downloaded (they
-might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.7"
-or "zlib127") so that you have directories called "zlib" and "libpng".
+might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.8"
+or "zlib128") so that you have directories called "zlib" and "libpng".

 Your directory structure should look like this:

@@ -75,8 +120,7 @@ Your directory structure should look like this:
      libpng  (this directory)
          INSTALL (this file)
          README
-          *.h
-          *.c
+          *.h, *.c  => libpng source files
          CMakeLists.txt    =>  "cmake" script
          configuration files:
             configure.ac, configure, Makefile.am, Makefile.in,
@@ -84,15 +128,10 @@ Your directory structure should look like this:
             libpng-config.in, aclocal.m4, config.h.in, config.sub,
             depcomp, install-sh, mkinstalldirs, test-pngtest.sh
          contrib
-             gregbook
-             libtests
-             pngminim
-             pngminus
-             pngsuite
-             visupng
+             arm-neon, conftest, examples, gregbook, libtests, pngminim,
+             pngminus, pngsuite, tools, visupng
          projects
-             visualc71
-             vstudio
+             cbuilder5, owatcom, visualc71, vstudio, xcode
          scripts
             makefile.*
             *.def (module definition files)
@@ -100,29 +139,31 @@ Your directory structure should look like this:
          pngtest.png
          etc.
      zlib
-          README
-          *.h
-          *.c
-          contrib
-          etc.
+          README, *.h, *.c contrib, etc.

 If the line endings in the files look funny, you may wish to get the other
 distribution of libpng.  It is available in both tar.gz (UNIX style line
 endings) and zip (DOS style line endings) formats.

+VI. Building with project files
+
 If you are building libpng with MSVC, you can enter the
-libpng projects\visualc6 or visualc71 directory and follow the instructions
+libpng projects\visualc71 or vstudio directory and follow the instructions
 in README.txt.

 Otherwise enter the zlib directory and follow the instructions in zlib/README,
 then come back here and run "configure" or choose the appropriate
 makefile.sys in the scripts directory.

+VII. Building with makefiles
+
 Copy the file (or files) that you need from the
 scripts directory into this directory, for example

   MSDOS example: copy scripts\makefile.msc makefile
-   UNIX example:    cp scripts/makefile.std makefile
+                  copy scripts\pnglibconf.h.prebuilt pnglibconf.h
+   UNIX example:  cp scripts/makefile.std makefile
+                  cp scripts/pnglibconf.h.prebuilt pnglibconf.h

 Read the makefile to see if you need to change any source or
 target directories to match your preferences.
@@ -145,6 +186,197 @@ do that, run "make install" in the zlib directory first if necessary).
 Some also allow you to run "make test-installed" after you have
 run "make install".

+VIII. Configuring libpng for 16-bit platforms
+
+You will want to look into zconf.h to tell zlib (and thus libpng) that
+it cannot allocate more then 64K at a time.  Even if you can, the memory
+won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.
+
+IX. Configuring for DOS
+
+For DOS users who only have access to the lower 640K, you will
+have to limit zlib's memory usage via a png_set_compression_mem_level()
+call.  See zlib.h or zconf.h in the zlib library for more information.
+
+X. Configuring for Medium Model
+
+Libpng's support for medium model has been tested on most of the popular
+compilers.  Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
+defined, and FAR gets defined to far in pngconf.h, and you should be
+all set.  Everything in the library (except for zlib's structure) is
+expecting far data.  You must use the typedefs with the p or pp on
+the end for pointers (or at least look at them and be careful).  Make
+note that the rows of data are defined as png_bytepp, which is
+an "unsigned char far * far *".
+
+XI. Prepending a prefix to exported symbols
+
+Starting with libpng-1.6.0, you can configure libpng (when using the
+"configure" script) to prefix all exported symbols by means of the
+configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any
+string beginning with a letter and containing only uppercase
+and lowercase letters, digits, and the underscore (i.e., a C language
+identifier).  This creates a set of macros in pnglibconf.h, so this is
+transparent to applications; their function calls get transformed by
+the macros to use the modified names.
+
+XII. Configuring for compiler xxx:
+
+All includes for libpng are in pngconf.h.  If you need to add, change
+or delete an include, this is the place to do it.
+The includes that are not needed outside libpng are placed in pngpriv.h,
+which is only used by the routines inside libpng itself.
+The files in libpng proper only include pngpriv.h and png.h, which
+in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
+As of libpng-1.5.0, pngpriv.h also includes three other private header
+files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
+that previously appeared in the public headers.
+
+XIII. Removing unwanted object code
+
+There are a bunch of #define's in pngconf.h that control what parts of
+libpng are compiled.  All the defines end in _SUPPORTED.  If you are
+never going to use a capability, you can change the #define to #undef
+before recompiling libpng and save yourself code and data space, or
+you can turn off individual capabilities with defines that begin with
+PNG_NO_.
+
+In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
+
+You can also turn all of the transforms and ancillary chunk capabilities
+off en masse with compiler directives that define
+PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
+or all four, along with directives to turn on any of the capabilities that
+you do want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the
+extra transformations but still leave the library fully capable of reading
+and writing PNG files with all known public chunks. Use of the
+PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
+that is incapable of reading or writing ancillary chunks.  If you are
+not using the progressive reading capability, you can turn that off
+with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
+capability, which you'll still have).
+
+All the reading and writing specific code are in separate files, so the
+linker should only grab the files it needs.  However, if you want to
+make sure, or if you are building a stand alone library, all the
+reading files start with "pngr" and all the writing files start with "pngw".
+The files that don't match either (like png.c, pngtrans.c, etc.)
+are used for both reading and writing, and always need to be included.
+The progressive reader is in pngpread.c
+
+If you are creating or distributing a dynamically linked library (a .so
+or DLL file), you should not remove or disable any parts of the library,
+as this will cause applications linked with different versions of the
+library to fail if they call functions not available in your library.
+The size of the library itself should not be an issue, because only
+those sections that are actually used will be loaded into memory.
+
+XIV. Changes to the build and configuration of libpng in libpng-1.5.x
+
+Details of internal changes to the library code can be found in the CHANGES
+file and in the GIT repository logs.  These will be of no concern to the vast
+majority of library users or builders; however, the few who configure libpng
+to a non-default feature set may need to change how this is done.
+
+There should be no need for library builders to alter build scripts if
+these use the distributed build support - configure or the makefiles -
+however, users of the makefiles may care to update their build scripts
+to build pnglibconf.h where the corresponding makefile does not do so.
+
+Building libpng with a non-default configuration has changed completely.
+The old method using pngusr.h should still work correctly even though the
+way pngusr.h is used in the build has been changed; however, library
+builders will probably want to examine the changes to take advantage of
+new capabilities and to simplify their build system.
+
+A. Specific changes to library configuration capabilities
+
+The exact mechanism used to control attributes of API functions has
+changed.  A single set of operating system independent macro definitions
+is used and operating system specific directives are defined in
+pnglibconf.h
+
+As part of this the mechanism used to choose procedure call standards on
+those systems that allow a choice has been changed.  At present this only
+affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
+running on Intel processors.  As before, PNGAPI is defined where required
+to control the exported API functions; however, two new macros, PNGCBAPI
+and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
+(PNGCAPI) for functions that must match a C library prototype (currently
+only png_longjmp_ptr, which must match the C longjmp function.)  The new
+approach is documented in pngconf.h
+
+Despite these changes, libpng 1.5.0 only supports the native C function
+calling standard on those platforms tested so far (__cdecl on Microsoft
+Windows).  This is because the support requirements for alternative
+calling conventions seem to no longer exist.  Developers who find it
+necessary to set PNG_API_RULE to 1 should advise the mailing list
+(png-mng-implement) of this and library builders who use Openwatcom and
+therefore set PNG_API_RULE to 2 should also contact the mailing list.
+
+B. Changes to the configuration mechanism
+
+Prior to libpng-1.5.0 library builders who needed to configure libpng
+had either to modify the exported pngconf.h header file to add system
+specific configuration or had to write feature selection macros into
+pngusr.h and cause this to be included into pngconf.h by defining
+PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
+application built without PNG_USER_CONFIG defined would see the
+unmodified, default, libpng API and thus would probably fail to link.
+
+These mechanisms still work in the configure build and in any makefile
+build that builds pnglibconf.h, although the feature selection macros
+have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
+processed only once, at the time the exported header file pnglibconf.h is
+built.  pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
+after the build of pnglibconf.h and it is never included in an application
+build.
+
+The formerly used alternative of adding a list of feature macros to the
+CPPFLAGS setting in the build also still works; however, the macros will be
+copied to pnglibconf.h and this may produce macro redefinition warnings
+when the individual C files are compiled.
+
+All configuration now only works if pnglibconf.h is built from
+scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
+(the original author of awk) maintains C source code of that awk and this
+and all known later implementations (often called by subtly different
+names - nawk and gawk for example) are adequate to build pnglibconf.h.
+The Sun Microsystems (now Oracle) program 'awk' is an earlier version
+and does not work; this may also apply to other systems that have a
+functioning awk called 'nawk'.
+
+Configuration options are now documented in scripts/pnglibconf.dfa.  This
+file also includes dependency information that ensures a configuration is
+consistent; that is, if a feature is switched off, dependent features are
+also switched off.  As a recommended alternative to using feature macros in
+pngusr.h a system builder may also define equivalent options in pngusr.dfa
+(or, indeed, any file) and add that to the configuration by setting
+DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
+how to do this, and also illustrate a case where pngusr.h is still required.
+
+After you have built libpng, the definitions that were recorded in
+pnglibconf.h are available to your application (pnglibconf.h is included
+in png.h and gets installed alongside png.h and pngconf.h in your
+$PREFIX/include directory).  Do not edit pnglibconf.h after you have built
+libpng, because than the settings would not accurately reflect the settings
+that were used to build libpng.
+
+XV. Configuring libpng for multiprocessing
+
+Libpng uses setjmp()/longjmp() for error handling.  Unfortunately setjmp()
+is known to be not thread-safe on some platforms and we don't know of
+any platform where it is guaranteed to be thread-safe.  Therefore, if
+your application is going to be using multiple threads, you should
+configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with
+-DPNG_NO_SETJMP on your compile line, or with
+
+  #undef PNG_SETJMP_SUPPORTED
+
+in your pnglibconf.h or pngusr.h.
+
+XVI. Other sources of information about libpng:
+
 Further information can be found in the README and libpng-manual.txt
 files, in the individual makefiles, in png.h, and the manual pages
 libpng.3 and png.5.
@@ -162,7 +394,7 @@ CFLAGS="-Wall -O -funroll-loops \
 --with-pkgconfigdir=/usr/lib/pkgconfig --includedir=/usr/include

 You can alternatively specify --includedir=/usr/include, /usr/local/include,
-/usr/include/libpng%NN%, or whatever.
+/usr/include/libpng16, or whatever.

 If you find that the configure script is out-of-date or is not supporting
 your platform properly, try running autogen.sh to regenerate "configure",
--- a/4
+++ b/4
@@ -10,7 +10,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.6.9beta02, January 1, 2014, are
+libpng versions 1.2.6, August 15, 2004, through 1.6.15, November 20, 2014, are
 Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -108,4 +108,4 @@ certification mark of the Open Source Initiative.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-January 1, 2014
+November 20, 2014
--- a/Makefile.am
+++ b/Makefile.am
@@ -7,7 +7,7 @@ PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
 ACLOCAL_AMFLAGS = -I scripts

 # test programs - run on make check, make distcheck
-check_PROGRAMS= pngtest pngunknown pngstest pngvalid
+check_PROGRAMS= pngtest pngunknown pngstest pngvalid pngimage

 # Utilities - installed
 bin_PROGRAMS= pngfix png-fix-itxt
@@ -34,6 +34,9 @@ pngstest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 pngunknown_SOURCES = contrib/libtests/pngunknown.c
 pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la

+pngimage_SOURCES = contrib/libtests/pngimage.c
+pngimage_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
 pngfix_SOURCES = contrib/tools/pngfix.c
 pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la

@@ -59,7 +62,8 @@ TESTS =\
   tests/pngstest-4a16 tests/pngstest-6a08 tests/pngstest-6a16\
   tests/pngstest-error tests/pngunknown-IDAT\
   tests/pngunknown-discard tests/pngunknown-if-safe tests/pngunknown-sAPI\
-   tests/pngunknown-sTER tests/pngunknown-save tests/pngunknown-vpAg
+   tests/pngunknown-sTER tests/pngunknown-save tests/pngunknown-vpAg\
+   tests/pngimage-quick tests/pngimage-full

 # These tests are expected, and required, to fail:
 XFAIL_TESTS = tests/pngstest-error
@@ -212,6 +216,7 @@ pngtest.o: pnglibconf.h
 contrib/libtests/makepng.o: pnglibconf.h
 contrib/libtests/pngstest.o: pnglibconf.h
 contrib/libtests/pngunknown.o: pnglibconf.h
+contrib/libtests/pngimage.o: pnglibconf.h
 contrib/libtests/pngvalid.o: pnglibconf.h
 contrib/libtests/readpng.o: pnglibconf.h
 contrib/libtests/tarith.o: pnglibconf.h
--- a/27
+++ b/27
@@ -1,4 +1,4 @@
-README for libpng version 1.6.9beta02 - January 1, 2014 (shared library 16.0)
+README for libpng version 1.6.15 - November 20, 2014 (shared library 16.0)
 See the note about version numbers near the top of png.h

 See INSTALL for instructions on how to install libpng.
@@ -23,18 +23,25 @@ earlier versions if you are using a shared library.  The type of the
 png_uint_32, which will affect shared-library applications that use
 this function.

-To avoid problems with changes to the internals of png_info_struct,
+To avoid problems with changes to the internals of png info_struct,
 new APIs have been made available in 0.95 to avoid direct application
 access to info_ptr.  These functions are the png_set_<chunk> and
 png_get_<chunk> functions.  These functions should be used when
 accessing/storing the info_struct data, rather than manipulating it
 directly, to avoid such problems in the future.

-It is important to note that the APIs do not make current programs
+It is important to note that the APIs did not make current programs
 that access the info struct directly incompatible with the new
-library.  However, it is strongly suggested that new programs use
-the new APIs (as shown in example.c and pngtest.c), and older programs
-be converted to the new format, to facilitate upgrades in the future.
+library, through libpng-1.2.x.  In libpng-1.4.x, which was meant to
+be a transitional release, members of the png_struct and the
+info_struct can still be accessed, but the compiler will issue a
+warning about deprecated usage.  Since libpng-1.5.0, direct access
+to these structs is not allowed, and the definitions of the structs
+reside in private pngstruct.h and pnginfo.h header files that are not
+accessible to applications.  It is strongly suggested that new
+programs use the new APIs (as shown in example.c and pngtest.c), and
+older programs be converted to the new format, to facilitate upgrades
+in the future.
 ****

 Additions since 0.90 include the ability to compile libpng as a
@@ -87,6 +94,12 @@ This code is currently being archived at libpng.sf.net in the
 [DOWNLOAD] area, and at ftp://ftp.simplesystems.org.  If you can't find it
 in any of those places, e-mail me, and I'll help you find it.

+I am not a lawyer, but I believe that the Export Control Classification
+Number (ECCN) for libpng is EAR99, which means not subject to export
+controls or International Traffic in Arms Regulations (ITAR) because it
+is open source, publicly available software, that does not contain any
+encryption software.  See the EAR, paragraphs 734.3(b)(3) and 734.7(b).
+
 If you have any code changes, requests, problems, etc., please e-mail
 them to me.  Also, I'd appreciate any make files or project files,
 and any modifications you needed to make to get libpng to compile,
@@ -177,7 +190,7 @@ Files in this distribution:
       pngminus         =>  Simple pnm2png and png2pnm programs
       pngsuite         =>  Test images
       tools            =>  Various tools
-       visupng      =>  Contains a MSVC workspace for VisualPng
+       visupng          =>  Contains a MSVC workspace for VisualPng
      projects      =>  Contains project files and workspaces for
                        building a DLL
       owatcom          =>  Contains a WATCOM project for building libpng
--- a/2
+++ b/2
@@ -6,10 +6,12 @@ Better C++ wrapper/full C++ implementation?
 Fix problem with C++ and EXTERN "C".
 cHRM transformation.
 Remove setjmp/longjmp usage in favor of returning error codes.
+Palette creation.
 Add "grayscale->palette" transformation and "palette->grayscale" detection.
 Improved dithering.
 Multi-lingual error and warning message support.
 Complete sRGB transformation (presently it simply uses gamma=0.45455).
+Make profile checking optional via a png_set_something() call.
 Man pages for function calls.
 Better documentation.
 Better filter selection
--- a/arm/arm_init.c
+++ b/arm/arm_init.c
@@ -1,9 +1,9 @@

 /* arm_init.c - NEON optimised filter functions
 *
- * Copyright (c) 2013 Glenn Randers-Pehrson
+ * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.6 [September 16, 2013]
+ * Last changed in libpng 1.6.10 [March 6, 2014]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -19,132 +19,33 @@
 #ifdef PNG_READ_SUPPORTED
 #if PNG_ARM_NEON_OPT > 0
 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
-#include <signal.h> /* for sig_atomic_t */
-
-#ifdef __ANDROID__
-/* Linux provides access to information about CPU capabilites via
- * /proc/self/auxv, however Android blocks this while still claiming to be
- * Linux.  The Andoid NDK, however, provides appropriate support.
+/* WARNING: it is strongly recommended that you do not build libpng with
+ * run-time checks for CPU features if at all possible.  In the case of the ARM
+ * NEON instructions there is no processor-specific way of detecting the
+ * presence of the required support, therefore run-time detection is extremely
+ * OS specific.
 *
- * Documentation: http://www.kandroid.org/ndk/docs/CPU-ARM-NEON.html
+ * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing
+ * a fragment of C source code which defines the png_have_neon function.  There
+ * are a number of implementations in contrib/arm-neon, but the only one that
+ * has partial support is contrib/arm-neon/linux.c - a generic Linux
+ * implementation which reads /proc/cpufino.
 */
-#include <cpu-features.h>
+#ifndef PNG_ARM_NEON_FILE
+#  ifdef __linux__
+#     define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c"
+#  endif
+#endif

-static int
-png_have_neon(png_structp png_ptr)
-{
-   /* This is a whole lot easier than the mess below, however it is probably
-    * implemented as below, therefore it is better to cache the result (these
-    * function calls may be slow!)
-    */
-   PNG_UNUSED(png_ptr)
-   return android_getCpuFamily() == ANDROID_CPU_FAMILY_ARM &&
-      (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) != 0;
-}
-#elif defined(__linux__)
-/* The generic __linux__ implementation requires reading /proc/self/auxv and
- * looking at each element for one that records NEON capabilities.
- */
-#include <unistd.h> /* for POSIX 1003.1 */
-#include <errno.h>  /* for EINTR */
+#ifdef PNG_ARM_NEON_FILE

-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <elf.h>
-#include <asm/hwcap.h>
+#include <signal.h> /* for sig_atomic_t */
+static int png_have_neon(png_structp png_ptr);
+#include PNG_ARM_NEON_FILE

-/* A read call may be interrupted, in which case it returns -1 and sets errno to
- * EINTR if nothing was done, otherwise (if something was done) a partial read
- * may result.
- */
-static size_t
-safe_read(png_structp png_ptr, int fd, void *buffer_in, size_t nbytes)
-{
-   size_t ntotal = 0;
-   char *buffer = png_voidcast(char*, buffer_in);
-
-   while (nbytes > 0)
-   {
-      unsigned int nread;
-      int iread;
-
-      /* Passing nread > INT_MAX to read is implementation defined in POSIX
-       * 1003.1, therefore despite the unsigned argument portable code must
-       * limit the value to INT_MAX!
-       */
-      if (nbytes > INT_MAX)
-         nread = INT_MAX;
-
-      else
-         nread = (unsigned int)/*SAFE*/nbytes;
-
-      iread = read(fd, buffer, nread);
-
-      if (iread == -1)
-      {
-         /* This is the devil in the details, a read can terminate early with 0
-          * bytes read because of EINTR, yet it still returns -1 otherwise end
-          * of file cannot be distinguished.
-          */
-         if (errno != EINTR)
-         {
-            png_warning(png_ptr, "/proc read failed");
-            return 0; /* I.e., a permanent failure */
-         }
-      }
-
-      else if (iread < 0)
-      {
-         /* Not a valid 'read' result: */
-         png_warning(png_ptr, "OS /proc read bug");
-         return 0;
-      }
-
-      else if (iread > 0)
-      {
-         /* Continue reading until a permanent failure, or EOF */
-         buffer += iread;
-         nbytes -= (unsigned int)/*SAFE*/iread;
-         ntotal += (unsigned int)/*SAFE*/iread;
-      }
-
-      else
-         return ntotal;
-   }
-
-   return ntotal; /* nbytes == 0 */
-}
-
-static int
-png_have_neon(png_structp png_ptr)
-{
-   int fd = open("/proc/self/auxv", O_RDONLY);
-   Elf32_auxv_t aux;
-
-   /* Failsafe: failure to open means no NEON */
-   if (fd == -1)
-   {
-      png_warning(png_ptr, "/proc/self/auxv open failed");
-      return 0;
-   }
-
-   while (safe_read(png_ptr, fd, &aux, sizeof aux) == sizeof aux)
-   {
-      if (aux.a_type == AT_HWCAP && (aux.a_un.a_val & HWCAP_NEON) != 0)
-      {
-         close(fd);
-         return 1;
-      }
-   }
-
-   close(fd);
-   return 0;
-}
-#else
-   /* We don't know how to do a run-time check on this system */
-#  error "no support for run-time ARM NEON checks"
-#endif /* OS checks */
+#else  /* PNG_ARM_NEON_FILE */
+#  error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks"
+#endif /* PNG_ARM_NEON_FILE */
 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */

 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED
--- a/configure.ac
+++ b/configure.ac
@@ -18,7 +18,7 @@ AC_PREREQ([2.68])

 dnl Version number stuff here:

-AC_INIT([libpng],[1.6.9beta02],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.15],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts])

 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -39,10 +39,10 @@ dnl automake, so the following is not necessary (and is not defined anyway):
 dnl AM_PREREQ([1.11.2])
 dnl stop configure from automagically running automake

-PNGLIB_VERSION=1.6.9beta02
+PNGLIB_VERSION=1.6.15
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=9
+PNGLIB_RELEASE=15

 dnl End of version number stuff

@@ -310,7 +310,7 @@ AC_ARG_ENABLE([arm-neon],
 AM_CONDITIONAL([PNG_ARM_NEON],
   [test "$enable_arm_neon" != 'no' &&
    case "$host_cpu" in
-      arm*) :;;
+      arm*|aarch64*) :;;
      *)    test "$enable_arm_neon" != '';;
    esac])

--- a/contrib/arm-neon/README
+++ b/contrib/arm-neon/README
@@ -0,0 +1,83 @@
+OPERATING SYSTEM SPECIFIC ARM NEON DETECTION
+--------------------------------------------
+
+Detection of the ability to exexcute ARM NEON on an ARM processor requires
+operating system support.  (The information is not available in user mode.)
+
+HOW TO USE THIS
+---------------
+
+This directory contains C code fragments that can be included in arm/arm_init.c
+by setting the macro PNG_ARM_NEON_FILE to the file name in "" or <> at build
+time.  This setting is not recorded in pnglibconf.h and can be changed simply by
+rebuilding arm/arm_init.o with the required macro definition.
+
+For any of this code to be used the ARM NEON code must be enabled and run time
+checks must be supported.  I.e.:
+
+#if PNG_ARM_NEON_OPT > 0
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-arm-neon=check
+
+Apart from the basic Linux implementation in contrib/arm-neon/linux.c this code
+is unsupported.  That means that it is not even compiled on a regular basis and
+may be broken in any given minor release.
+
+FILE FORMAT
+-----------
+
+Each file documents its testing status as of the last time it was tested (which
+may have been a long time ago):
+
+STATUS: one of:
+   SUPPORTED: This indicates that the file is included in the regularly
+         performed test builds and bugs are fixed when discovered.
+   COMPILED: This indicates that the code did compile at least once.  See the
+         more detailed description for the extent to which the result was
+         successful.
+   TESTED: This means the code was fully compiled into the libpng test programs
+         and these were run at least once.
+
+BUG REPORTS: an email address to which to send reports of problems
+
+The file is a fragment of C code. It should not define any 'extern' symbols;
+everything should be static.  It must define the function:
+
+static int png_have_neon(png_structp png_ptr);
+
+That function must return 1 if ARM NEON instructions are supported, 0 if not.
+It must not execute png_error unless it detects a bug.  A png_error will prevent
+the reading of the PNG and in the future, writing too.
+
+BUG REPORTS
+-----------
+
+If you mail a bug report for any file that is not SUPPORTED there may only be
+limited response.  Consider fixing it and sending a patch to fix the problem -
+this is more likely to result in action.
+
+CONTRIBUTIONS
+-------------
+
+You may send contributions of new implementations to
+png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+possible.  Obviously OS dependencies are to be expected.  If you submit code you
+must have the authors permission and it must have a license that is acceptable
+to the current maintainer; in particular that license must permit modification
+and redistribution.
+
+Please try to make the contribution a single file and give the file a clear and
+unambiguous name that identifies the target OS.  If multiple files really are
+required put them all in a sub-directory.
+
+You must also be prepared to handle bug reports from users of the code, either
+by joining the png-mng-implement mailing list or by providing an email for the
+"BUG REPORTS" entry or both.  Please make sure that the header of the file
+contains the STATUS and BUG REPORTS fields as above.
+
+Please list the OS requirements as precisely as possible.  Ideally you should
+also list the environment in which the code has been tested and certainly list
+any environments where you suspect it might not work.
--- a/contrib/arm-neon/android-ndk.c
+++ b/contrib/arm-neon/android-ndk.c
@@ -0,0 +1,39 @@
+/* contrib/arm-neon/android-ndk.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by John Bowler, 2014.
+ * Last changed in libpng 1.6.10 [March 6, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: COMPILED, UNTESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for the Android NDK, see:
+ *
+ * Documentation:
+ *    http://www.kandroid.org/ndk/docs/CPU-ARM-NEON.html
+ *    http://code.google.com/p/android/issues/detail?id=49065
+ *
+ * NOTE: this requires that libpng is built against the Android NDK and linked
+ * with an implementation of the Android ARM 'cpu-features' library.  The code
+ * has been compiled only, not linked: no version of the library has been found,
+ * only the header files exist in the NDK.
+ */
+#include <cpu-features.h>
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   /* This is a whole lot easier than the linux code, however it is probably
+    * implemented as below, therefore it is better to cache the result (these
+    * function calls may be slow!)
+    */
+   PNG_UNUSED(png_ptr)
+   return android_getCpuFamily() == ANDROID_CPU_FAMILY_ARM &&
+      (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) != 0;
+}
--- a/contrib/arm-neon/linux-auxv.c
+++ b/contrib/arm-neon/linux-auxv.c
@@ -0,0 +1,120 @@
+/* contrib/arm-neon/linux-auxv.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ * Last changed in libpng 1.6.10 [March 6, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ * 
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: COMPILED, TESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for Linux versions which allow access to
+ * /proc/self/auxv.  This is probably faster, cleaner and safer than the code to
+ * read /proc/cpuinfo in contrib/arm-neon/linux, however it is yet another piece
+ * of potentially untested code and has more complex dependencies than the code
+ * to read cpuinfo.
+ *
+ * This generic __linux__ implementation requires reading /proc/self/auxv and
+ * looking at each element for one that records NEON capabilities.
+ */
+#include <unistd.h> /* for POSIX 1003.1 */
+#include <errno.h>  /* for EINTR */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <elf.h>
+#include <asm/hwcap.h>
+
+/* A read call may be interrupted, in which case it returns -1 and sets errno to
+ * EINTR if nothing was done, otherwise (if something was done) a partial read
+ * may result.
+ */
+static size_t
+safe_read(png_structp png_ptr, int fd, void *buffer_in, size_t nbytes)
+{
+   size_t ntotal = 0;
+   char *buffer = png_voidcast(char*, buffer_in);
+
+   while (nbytes > 0)
+   {
+      unsigned int nread;
+      int iread;
+
+      /* Passing nread > INT_MAX to read is implementation defined in POSIX
+       * 1003.1, therefore despite the unsigned argument portable code must
+       * limit the value to INT_MAX!
+       */
+      if (nbytes > INT_MAX)
+         nread = INT_MAX;
+
+      else
+         nread = (unsigned int)/*SAFE*/nbytes;
+
+      iread = read(fd, buffer, nread);
+
+      if (iread == -1)
+      {
+         /* This is the devil in the details, a read can terminate early with 0
+          * bytes read because of EINTR, yet it still returns -1 otherwise end
+          * of file cannot be distinguished.
+          */
+         if (errno != EINTR)
+         {
+            png_warning(png_ptr, "/proc read failed");
+            return 0; /* I.e., a permanent failure */
+         }
+      }
+
+      else if (iread < 0)
+      {
+         /* Not a valid 'read' result: */
+         png_warning(png_ptr, "OS /proc read bug");
+         return 0;
+      }
+
+      else if (iread > 0)
+      {
+         /* Continue reading until a permanent failure, or EOF */
+         buffer += iread;
+         nbytes -= (unsigned int)/*SAFE*/iread;
+         ntotal += (unsigned int)/*SAFE*/iread;
+      }
+
+      else
+         return ntotal;
+   }
+
+   return ntotal; /* nbytes == 0 */
+}
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   int fd = open("/proc/self/auxv", O_RDONLY);
+   Elf32_auxv_t aux;
+
+   /* Failsafe: failure to open means no NEON */
+   if (fd == -1)
+   {
+      png_warning(png_ptr, "/proc/self/auxv open failed");
+      return 0;
+   }
+
+   while (safe_read(png_ptr, fd, &aux, sizeof aux) == sizeof aux)
+   {
+      if (aux.a_type == AT_HWCAP && (aux.a_un.a_val & HWCAP_NEON) != 0)
+      {
+         close(fd);
+         return 1;
+      }
+   }
+
+   close(fd);
+   return 0;
+}
--- a/contrib/arm-neon/linux.c
+++ b/contrib/arm-neon/linux.c
@@ -0,0 +1,161 @@
+/* contrib/arm-neon/linux.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by John Bowler, 2014.
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: SUPPORTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for Linux by reading the widely available
+ * pseudo-file /proc/cpuinfo.
+ *
+ * This code is strict ANSI-C and is probably moderately portable, it does
+ * however use <stdio.h> and assumes that /proc/cpuinfo is never localized.
+ */
+#include <stdio.h>
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   FILE *f = fopen("/proc/cpuinfo", "rb");
+
+   if (f != NULL)
+   {
+      /* This is a simple state machine which reads the input byte-by-byte until
+       * it gets a match on the 'neon' feature or reaches the end of the stream.
+       */
+      static const char ch_feature[] = { 70, 69, 65, 84, 85, 82, 69, 83 };
+      static const char ch_neon[] = { 78, 69, 79, 78 };
+
+      enum
+      {
+         StartLine, Feature, Colon, StartTag, Neon, HaveNeon, SkipTag, SkipLine
+      }  state;
+      int counter;
+
+      for (state=StartLine, counter=0;;)
+      {
+         int ch = fgetc(f);
+
+         if (ch == EOF)
+         {
+            /* EOF means error or end-of-file, return false; neon at EOF is
+             * assumed to be a mistake.
+             */
+            fclose(f);
+            return 0;
+         }
+
+         switch (state)
+         {
+            case StartLine:
+               /* Match spaces at the start of line */
+               if (ch <= 32) /* skip control characters and space */
+                  break;
+
+               counter=0;
+               state = Feature;
+               /* FALL THROUGH */
+
+            case Feature:
+               /* Match 'FEATURE', ASCII case insensitive. */
+               if ((ch & ~0x20) == ch_feature[counter])
+               {
+                  if (++counter == (sizeof ch_feature))
+                     state = Colon;
+                  break;
+               }
+               
+               /* did not match 'feature' */
+               state = SkipLine;
+               /* FALL THROUGH */
+
+            case SkipLine:
+            skipLine:
+               /* Skip everything until we see linefeed or carriage return */
+               if (ch != 10 && ch != 13)
+                  break;
+
+               state = StartLine;
+               break;
+
+            case Colon:
+               /* Match any number of space or tab followed by ':' */
+               if (ch == 32 || ch == 9)
+                  break;
+
+               if (ch == 58) /* i.e. ':' */
+               {
+                  state = StartTag;
+                  break;
+               }
+
+               /* Either a bad line format or a 'feature' prefix followed by
+                * other characters.
+                */
+               state = SkipLine;
+               goto skipLine;
+
+            case StartTag:
+               /* Skip space characters before a tag */
+               if (ch == 32 || ch == 9)
+                  break;
+
+               state = Neon;
+               counter = 0;
+               /* FALL THROUGH */
+
+            case Neon:
+               /* Look for 'neon' tag */
+               if ((ch & ~0x20) == ch_neon[counter])
+               {
+                  if (++counter == (sizeof ch_neon))
+                     state = HaveNeon;
+                  break;
+               }
+
+               state = SkipTag;
+               /* FALL THROUGH */
+
+            case SkipTag:
+               /* Skip non-space characters */
+               if (ch == 10 || ch == 13)
+                  state = StartLine;
+
+               else if (ch == 32 || ch == 9)
+                  state = StartTag;
+               break;
+
+            case HaveNeon:
+               /* Have seen a 'neon' prefix, but there must be a space or new
+                * line character to terminate it.
+                */
+               if (ch == 10 || ch == 13 || ch == 32 || ch == 9)
+               {
+                  fclose(f);
+                  return 1;
+               }
+
+               state = SkipTag;
+               break;
+
+            default:
+               png_error(png_ptr, "png_have_neon: internal error (bug)");
+         }
+      }
+   }
+
+#ifdef PNG_WARNINGS_SUPPORTED
+   else
+      png_warning(png_ptr, "/proc/cpuinfo open failed");
+#endif
+
+   return 0;
+}
--- a/contrib/examples/iccfrompng.c
+++ b/contrib/examples/iccfrompng.c
@@ -6,9 +6,9 @@
 * United States.
 *
 * Extract any icc profiles found in the given PNG files.  This is a simple
- * example of a program which extracts information from the header of a PNG file
+ * example of a program that extracts information from the header of a PNG file
 * without processing the image.  Notice that some header information may occur
- * after the image data, textual data and comments are an example; the approach
+ * after the image data. Textual data and comments are an example; the approach
 * in this file won't work reliably for such data because it only looks for the
 * information in the section of the file that preceeds the image data.
 *
--- a/contrib/examples/pngpixel.c
+++ b/contrib/examples/pngpixel.c
@@ -8,7 +8,7 @@
 * Read a single pixel value from a PNG file.
 *
 * This code illustrates basic 'by-row' reading of a PNG file using libpng.
- * Rows are read until a particular pixel is found, the value of this pixel is
+ * Rows are read until a particular pixel is found; the value of this pixel is
 * then printed on stdout.
 *
 * The code illustrates how to do this on interlaced as well as non-interlaced
@@ -56,7 +56,7 @@ component(png_const_bytep row, png_uint_32 x, unsigned int c,
      case 8: return row[0];
      case 16: return (row[0] << 8) + row[1];
      default:
-         /* This should never happen, it indicates a bug in this program or in
+         /* This should never happen; it indicates a bug in this program or in
          * libpng itself:
          */
         fprintf(stderr, "pngpixel: invalid bit depth %u\n", bit_depth);
@@ -132,7 +132,7 @@ print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
         return;

      default:
-         png_error(png_ptr, "invalid color type");
+         png_error(png_ptr, "pngpixel: invalid color type");
   }
 }

--- a/contrib/gregbook/Makefile.mingw32
+++ b/contrib/gregbook/Makefile.mingw32
@@ -47,7 +47,8 @@ CC = gcc
 #CC = i386-mingw32msvc-gcc #	e.g., Linux -> Win32 cross-compilation
 LD = $(CC)
 RM = rm -f
-CFLAGS = -O -Wall $(INCS) $(MINGW_CCFLAGS)
+CPPFLAGS = $(INCS)
+CFLAGS = -O -Wall $(MINGW_CCFLAGS)
 # [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
 # [-ansi, -pedantic and -W can also be used]
 LDFLAGS = $(MINGW_LDFLAGS)
@@ -85,10 +86,10 @@ EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
 # implicit make rules -------------------------------------------------------

 .c$(O):
-	$(CC) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<

 %.pic$(O): %.c
-	$(CC) -c $(CFLAGS) -DPNG_BUILD_DLL -o $@ $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -DPNG_BUILD_DLL -o $@ $<


 # dependencies --------------------------------------------------------------
--- a/contrib/gregbook/Makefile.sgi
+++ b/contrib/gregbook/Makefile.sgi
@@ -53,7 +53,8 @@ CC = cc
 LD = cc
 RM = rm -f
 # ABI must be the same as that used to build libpng.
-ABI=
+ABI =
+CPPFLAGS =
 CFLAGS = $(ABI) -O -fullwarn $(INCS)
 LDFLAGS = $(ABI)
 O = .o
@@ -73,7 +74,7 @@ EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
 # implicit make rules -------------------------------------------------------

 .c$(O):
-	$(CC) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<


 # dependencies --------------------------------------------------------------
--- a/contrib/gregbook/Makefile.unx
+++ b/contrib/gregbook/Makefile.unx
@@ -59,14 +59,16 @@ INCS = $(PNGINC) $(ZINC) $(XINC)
 RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
 RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
 WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
-WLIBSs = $(PNGLIBs) $(ZLIBs)
+WLIBSs = $(PNGLIBs) $(ZLIBs) -lm

 CC = gcc
 LD = gcc
 RM = rm -f
-CFLAGS = -O -Wall $(INCS) -DFEATURE_LOOP
+CPPFLAGS = $(INCS) -DFEATURE_LOOP
+CFLAGS = -O -Wall
+#CFLAGS = -O -W -Wall -Wextra -pedantic -ansi
 # [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
-# [-ansi, -pedantic and -W can also be used]
+# [-ansi, -pedantic, -Wextra, and -W can also be used]
 LDFLAGS =
 O = .o
 E =
@@ -92,7 +94,7 @@ EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
 # implicit make rules -------------------------------------------------------

 .c$(O):
-	$(CC) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<


 # dependencies --------------------------------------------------------------
--- a/contrib/gregbook/Makefile.w32
+++ b/contrib/gregbook/Makefile.w32
@@ -53,7 +53,8 @@ WLIBS = $(PNGLIB) $(ZLIB)
 CC = cl
 LD = link
 RM = del
-CFLAGS = -nologo -O -W3 $(INCS) $(cvars)
+CPPFLAGS = $(INCS)
+CFLAGS = -nologo -O -W3 $(cvars)
 # [note that -W3 is an MSVC-specific compilation flag ("all warnings on")]
 # [see %devstudio%\vc\include\win32.mak for cvars macro definition]
 O = .obj
@@ -76,7 +77,7 @@ EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
 # implicit make rules -------------------------------------------------------

 .c$(O):
-	$(CC) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<


 # dependencies --------------------------------------------------------------
--- a/contrib/gregbook/readpng.c
+++ b/contrib/gregbook/readpng.c
@@ -100,7 +100,8 @@ int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)

    /* could pass pointers to user-defined error handlers instead of NULLs: */

-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), NULL, NULL,
+        NULL);
    if (!png_ptr)
        return 4;   /* out of memory */

--- a/contrib/gregbook/readpng2.c
+++ b/contrib/gregbook/readpng2.c
@@ -69,6 +69,7 @@ static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
                                 png_uint_32 row_num, int pass);
 static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr);
 static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg);
+static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg);



@@ -103,8 +104,8 @@ int readpng2_init(mainprog_info *mainprog_ptr)

    /* could also replace libpng warning-handler (final NULL), but no need: */

-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
-      readpng2_error_handler, NULL);
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), mainprog_ptr,
+      readpng2_error_handler, readpng2_warning_handler);
    if (!png_ptr)
        return 4;   /* out of memory */

@@ -447,6 +448,8 @@ static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)

    /* all done */

+    (void)info_ptr; /* Unused */
+
    return;
 }

@@ -467,7 +470,12 @@ void readpng2_cleanup(mainprog_info *mainprog_ptr)
 }


-
+static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg)
+{
+    fprintf(stderr, "readpng2 libpng warning: %s\n", msg);
+    fflush(stderr);
+    (void)png_ptr; /* Unused */
+}


 static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg)
--- a/contrib/gregbook/readppm.c
+++ b/contrib/gregbook/readppm.c
@@ -163,8 +163,12 @@ uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)

    /* now we can go ahead and just read the whole image */

-    fread(image_data, 1L, rowbytes*height, saved_infile);
-
+    if (fread(image_data, 1L, rowbytes*height, saved_infile) <
+       rowbytes*height) {
+        free (image_data);
+        image_data = NULL;
+        return NULL;
+    }

    return image_data;
 }
--- a/contrib/gregbook/rpng-x.c
+++ b/contrib/gregbook/rpng-x.c
@@ -26,6 +26,8 @@
    - 1.14:  added support for X resources (thanks to Gerhard Niklasch)
    - 2.00:  dual-licensed (added GNU GPL)
    - 2.01:  fixed improper display of usage screen on PNG error(s)
+    - 2.02:  Added "void(argc);" statement to quiet pedantic compiler warnings
+             about unused variable (GR-P)

  ---------------------------------------------------------------------------

@@ -80,7 +82,7 @@

 #define PROGNAME  "rpng-x"
 #define LONGNAME  "Simple PNG Viewer for X"
-#define VERSION   "2.01 of 16 March 2008"
+#define VERSION   "2.02 of 15 June 2014"
 #define RESNAME   "rpng"        /* our X resource application name */
 #define RESCLASS  "Rpng"        /* our X resource class name */

@@ -279,15 +281,17 @@ int main(int argc, char **argv)
          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg] file.png\n"
          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n",
+          PROGNAME, default_display_exponent);
+
+        fprintf(stderr, "\n"
          "\t\t  to the product of the lookup-table exponent (varies)\n"
          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
          "    bg  \tdesired background color in 7-character hex RGB format\n"
          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
          "\t\t  used with transparent images\n"
          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
-          "\n", PROGNAME, default_display_exponent);
+          "is displayed) to quit.\n");
        exit(1);
    }

@@ -419,6 +423,8 @@ int main(int argc, char **argv)

    rpng_x_cleanup();

+    (void)argc; /* Unused */
+
    return 0;
 }

--- a/contrib/gregbook/rpng2-win.c
+++ b/contrib/gregbook/rpng2-win.c
@@ -33,6 +33,8 @@
    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
              unexpected-EOF and file-read-error cases
    - 2.03:  removed runtime MMX-enabling/disabling and obsolete -mmx* options
+    - 2.04:  
+             (GR-P)

  ---------------------------------------------------------------------------

--- a/contrib/gregbook/rpng2-x.c
+++ b/contrib/gregbook/rpng2-x.c
@@ -41,7 +41,11 @@
              unexpected-EOF and file-read-error cases; fixed Trace() cut-and-
              paste bugs
    - 2.03:  deleted runtime MMX-enabling/disabling and obsolete -mmx* options
+    - 2.04:  Added "void(foo);" statements to quiet pedantic compiler warnings
+             about unused variables (GR-P)

+  TO DO:
+             use nanosleep() instead of usleep(), which is obsolete/deprecated.
  ---------------------------------------------------------------------------

      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
@@ -95,7 +99,7 @@

 #define PROGNAME  "rpng2-x"
 #define LONGNAME  "Progressive PNG Viewer for X"
-#define VERSION   "2.03 of 25 February 2010"
+#define VERSION   "2.04 of 15 June 2014"
 #define RESNAME   "rpng2"       /* our X resource application name */
 #define RESCLASS  "Rpng"       /* our X resource class name */

@@ -111,6 +115,18 @@
 #include <X11/Xos.h>
 #include <X11/keysym.h>   /* defines XK_* macros */

+#if _POSIX_C_SOURCE >= 199309L /* have nanosleep() */
+# undef usleep
+# define usleep(usec) {        \
+   struct timespec ts;         \
+   ts.tv_nsec = (usec) * 1000; \
+   nanosleep(&ts, NULL); }
+#  endif
+
+#ifndef usleep /* have neither nanosleep() nor usleep() */
+#  define usleep(x) sleep(((x)+499999)/1000000)
+#endif
+
 #ifdef VMS
 #  include <unistd.h>
 #endif
@@ -456,40 +472,47 @@ int main(int argc, char **argv)
        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
        readpng2_version_info();
        fprintf(stderr, "\n"
-          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+          "Usage:   ");
+        fprintf(stderr,
+          "%s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+          "        %*s [-usleep dur | -timing] [-pause]\n",
+          PROGNAME, (int)strlen(PROGNAME), " ");
+        fprintf(stderr,
 #ifdef FEATURE_LOOP
-          "        %*s [-usleep dur | -timing] [-pause] [-loop [sec]] file.png\n\n"
-#else
-          "        %*s [-usleep dur | -timing] [-pause] file.png\n\n"
+          "        [-loop [sec]]"
 #endif
+          " file.png\n\n");
+        fprintf(stderr,
          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n",
+          default_display_exponent);
+        fprintf(stderr,
          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
          "    bg  \tdesired background color in 7-character hex RGB format\n"
          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
          "\t\t  used with transparent images; overrides -bgpat\n"
          "    pat \tdesired background pattern number (0-%d); used with\n"
-          "\t\t  transparent images; overrides -bgcolor\n"
+          "\t\t  transparent images; overrides -bgcolor\n",
+          num_bgpat-1);
 #ifdef FEATURE_LOOP
+        fprintf(stderr, 
          "    -loop\tloops through background images after initial display\n"
          "\t\t  is complete (depends on -bgpat)\n"
-          "    sec \tseconds to display each background image (default = 2)\n"
+          "    sec \tseconds to display each background image (default = 2)\n");
 #endif
+        fprintf(stderr, 
          "    dur \tduration in microseconds to wait after displaying each\n"
          "\t\t  row (for demo purposes)\n"
          "    -timing\tenables delay for every block read, to simulate modem\n"
          "\t\t  download of image (~36 Kbps)\n"
          "    -pause\tpauses after displaying each pass until mouse clicked\n"
          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
-          "\n", PROGNAME,
-          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat-1);
+          "is displayed) to quit.\n");
        exit(1);
    }

-
    if (!(infile = fopen(filename, "rb"))) {
        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
        ++error;
@@ -735,6 +758,8 @@ int main(int argc, char **argv)
    Trace((stderr, "about to call rpng2_x_cleanup()\n"))
    rpng2_x_cleanup();

+    (void)argc; /* Unused */
+
    return 0;
 }

@@ -1826,6 +1851,9 @@ static void rpng2_x_redisplay_image(ulg startcol, ulg startrow,
        XFlush(display);
    }

+    (void)startcol;
+    (void)width;
+
 } /* end function rpng2_x_redisplay_image() */


--- a/contrib/gregbook/writepng.c
+++ b/contrib/gregbook/writepng.c
@@ -90,7 +90,7 @@ int writepng_init(mainprog_info *mainprog_ptr)

    /* could also replace libpng warning-handler (final NULL), but no need: */

-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+    png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), mainprog_ptr,
      writepng_error_handler, NULL);
    if (!png_ptr)
        return 4;   /* out of memory */
--- a/contrib/libtests/fakepng.c
+++ b/contrib/libtests/fakepng.c
@@ -52,6 +52,6 @@ main(void)
   fwrite(signature, sizeof signature, 1, stdout);
   put_chunk(IHDR, sizeof IHDR);

-   for(;;)
+   for (;;)
      put_chunk(unknown, sizeof unknown);
 }
--- a/contrib/libtests/pngimage.c
+++ b/contrib/libtests/pngimage.c
--- a/contrib/libtests/pngunknown.c
+++ b/contrib/libtests/pngunknown.c
@@ -1,8 +1,8 @@

 /* pngunknown.c - test the read side unknown chunk handling
 *
- * Last changed in libpng 1.6.0 [February 14, 2013]
- * Copyright (c) 2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.10 [March 6, 2014]
+ * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by John Cunningham Bowler
 *
 * This code is released under the libpng license.
@@ -439,7 +439,7 @@ display_rc(const display *d, int strict)
 }

 /* libpng error and warning callbacks */
-PNG_FUNCTION(void, error, (png_structp png_ptr, const char *message),
+PNG_FUNCTION(void, (PNGCBAPI error), (png_structp png_ptr, const char *message),
   static PNG_NORETURN)
 {
   display *d = (display*)png_get_error_ptr(png_ptr);
@@ -448,7 +448,7 @@ PNG_FUNCTION(void, error, (png_structp png_ptr, const char *message),
   display_exit(d);
 }

-static void
+static void PNGCBAPI
 warning(png_structp png_ptr, const char *message)
 {
   display *d = (display*)png_get_error_ptr(png_ptr);
@@ -490,7 +490,7 @@ get_valid(display *d, png_infop info_ptr)
 }

 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
-static int
+static int PNGCBAPI
 read_callback(png_structp pp, png_unknown_chunkp pc)
 {
   /* This function mimics the behavior of png_set_keep_unknown_chunks by
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -1,7 +1,7 @@

 /* pngvalid.c - validate libpng by constructing then reading png files.
 *
- * Last changed in libpng 1.5.18 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.14 [October 23, 2014]
 * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by John Cunningham Bowler
 *
@@ -34,6 +34,16 @@
 #  include <fenv.h>
 #endif

+#ifndef FE_DIVBYZERO
+#  define FE_DIVBYZERO 0
+#endif
+#ifndef FE_INVALID
+#  define FE_INVALID 0
+#endif
+#ifndef FE_OVERFLOW
+#  define FE_OVERFLOW 0
+#endif
+
 /* Define the following to use this test against your installed libpng, rather
 * than the one being built here:
 */
@@ -122,11 +132,6 @@ typedef png_byte *png_const_bytep;
 #  endif
 #endif

-/* Fixups for various minimal builds */
-#ifndef PNG_ERROR_TEXT_SUPPORTED
-#  define png_error(a,b) png_err(a)
-#endif
-
 /***************************** EXCEPTION HANDLING *****************************/
 #ifdef PNG_FREESTANDING_TESTS
 #  include <cexcept.h>
@@ -152,6 +157,13 @@ define_exception_type(struct png_store*);
   &(ps)->exception_context
 #define context(ps,fault) anon_context(ps); png_store *fault

+/* This macro returns the number of elements in an array as an (unsigned int),
+ * it is necessary to avoid the inability of certain versions of GCC to use
+ * the value of a compile-time constant when performing range checks.  It must
+ * be passed an array name.
+ */
+#define ARRAY_SIZE(a) ((unsigned int)((sizeof (a))/(sizeof (a)[0])))
+
 /******************************* UTILITIES ************************************/
 /* Error handling is particularly problematic in production code - error
 * handlers often themselves have bugs which lead to programs that detect
@@ -391,9 +403,9 @@ next_format(png_bytep colour_type, png_bytep bit_depth,

   /* Palette images are restricted to 8 bit depth */
   if (*bit_depth <= 8
-#     ifdef DO_16BIT
+#ifdef DO_16BIT
         || (*colour_type != 3 && *bit_depth <= 16)
-#     endif
+#endif
      )
      return 1;

@@ -691,7 +703,7 @@ static png_uint_32
 random_32(void)
 {

-   for(;;)
+   for (;;)
   {
      png_byte mark[4];
      png_uint_32 result;
@@ -926,7 +938,7 @@ internal_error(png_store *ps, png_const_charp message)
 #endif /* PNG_READ_SUPPORTED */

 /* Functions to use as PNG callbacks. */
-static void
+static void PNGCBAPI
 store_error(png_structp ppIn, png_const_charp message) /* PNG_NORETURN */
 {
   png_const_structp pp = ppIn;
@@ -942,7 +954,7 @@ store_error(png_structp ppIn, png_const_charp message) /* PNG_NORETURN */
   }
 }

-static void
+static void PNGCBAPI
 store_warning(png_structp ppIn, png_const_charp message)
 {
   png_const_structp pp = ppIn;
@@ -1093,7 +1105,7 @@ store_image_check(PNG_CONST png_store* ps, png_const_structp pp, int iImage)
 }
 #endif /* PNG_READ_SUPPORTED */

-static void
+static void PNGCBAPI
 store_write(png_structp ppIn, png_bytep pb, png_size_t st)
 {
   png_const_structp pp = ppIn;
@@ -1121,7 +1133,7 @@ store_write(png_structp ppIn, png_bytep pb, png_size_t st)
   }
 }

-static void
+static void PNGCBAPI
 store_flush(png_structp ppIn)
 {
   UNUSED(ppIn) /*DOES NOTHING*/
@@ -1215,7 +1227,7 @@ store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
   }
 }

-static void
+static void PNGCBAPI
 store_read(png_structp ppIn, png_bytep pb, png_size_t st)
 {
   png_const_structp pp = ppIn;
@@ -1408,7 +1420,7 @@ store_pool_delete(png_store *ps, store_pool *pool)
 }

 /* The memory callbacks: */
-static png_voidp
+static png_voidp PNGCBAPI
 store_malloc(png_structp ppIn, png_alloc_size_t cb)
 {
   png_const_structp pp = ppIn;
@@ -1457,7 +1469,7 @@ store_malloc(png_structp ppIn, png_alloc_size_t cb)
   return new;
 }

-static void
+static void PNGCBAPI
 store_free(png_structp ppIn, png_voidp memory)
 {
   png_const_structp pp = ppIn;
@@ -1553,7 +1565,7 @@ set_store_for_write(png_store *ps, png_infopp ppi,

         else
 #     endif
-         ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+         ps->pwrite = png_create_write_struct(png_get_libpng_ver(NULL),
            ps, store_error, store_warning);

      png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
@@ -2676,7 +2688,7 @@ modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
 }

 /* The callback: */
-static void
+static void PNGCBAPI
 modifier_read(png_structp ppIn, png_bytep pb, png_size_t st)
 {
   png_const_structp pp = ppIn;
@@ -3160,10 +3172,10 @@ init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
      for (; i<256; ++i)
         tRNS[i] = 24;

-#     ifdef PNG_WRITE_tRNS_SUPPORTED
+#  ifdef PNG_WRITE_tRNS_SUPPORTED
         if (j > 0)
            png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
-#     endif
+#  endif
   }
 }

@@ -4101,7 +4113,7 @@ make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
         standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
            interlace_type, 0, 0, 0);

-         for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test)
+         for (test=0; test<ARRAY_SIZE(error_test); ++test)
         {
            make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
               test, name);
@@ -4680,7 +4692,7 @@ standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
   standard_info_part2(dp, pp, pi, nImages);
 }

-static void
+static void PNGCBAPI
 standard_info(png_structp pp, png_infop pi)
 {
   standard_display *dp = voidcast(standard_display*,
@@ -4692,7 +4704,7 @@ standard_info(png_structp pp, png_infop pi)
   standard_info_imp(dp, pp, pi, 1 /*only one image*/);
 }

-static void
+static void PNGCBAPI
 progressive_row(png_structp ppIn, png_bytep new_row, png_uint_32 y, int pass)
 {
   png_const_structp pp = ppIn;
@@ -5006,7 +5018,7 @@ standard_image_validate(standard_display *dp, png_const_structp pp, int iImage,
   dp->ps->validated = 1;
 }

-static void
+static void PNGCBAPI
 standard_end(png_structp ppIn, png_infop pi)
 {
   png_const_structp pp = ppIn;
@@ -5841,7 +5853,7 @@ transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
   }
 }

-static void
+static void PNGCBAPI
 transform_info(png_structp pp, png_infop pi)
 {
   transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
@@ -6048,7 +6060,7 @@ transform_image_validate(transform_display *dp, png_const_structp pp,
   dp->this.ps->validated = 1;
 }

-static void
+static void PNGCBAPI
 transform_end(png_structp ppIn, png_infop pi)
 {
   png_const_structp pp = ppIn;
@@ -6781,14 +6793,14 @@ image_transform_png_set_rgb_to_gray_ini(PNG_CONST image_transform *this,
          *  conversion adds another +/-2 in the 16-bit case and
          *  +/-(1<<(15-PNG_MAX_GAMMA_8)) in the 8-bit case.
          */
-         that->pm->limit += pow(
-#           if PNG_MAX_GAMMA_8 < 14
-               (that->this.bit_depth == 16 ? 8. :
-                  6. + (1<<(15-PNG_MAX_GAMMA_8)))
-#           else
-               8.
-#           endif
-               /65535, data.gamma);
+         that->pm->limit +=
+#        if PNG_MAX_GAMMA_8 < 14
+               pow((that->this.bit_depth == 16 ?
+                  8. : 6. + (1<<(15-PNG_MAX_GAMMA_8)))/65535, data.gamma);
+#        else
+               pow((that->this.bit_depth == 16 ?
+                  8. : 8. + (1<<(15-PNG_MAX_GAMMA_8)))/65535, data.gamma);
+#        endif
      }

      else
@@ -6806,13 +6818,12 @@ image_transform_png_set_rgb_to_gray_ini(PNG_CONST image_transform *this,
          * internal calculation errors, not the actual limit imposed by
          * pngvalid on the output errors.
          */
-         that->pm->limit += pow(
-#           if DIGITIZE
-               1.1
-#           else
-               1.
-#           endif
-               /255, data.gamma);
+         that->pm->limit +=
+#        if DIGITIZE
+             pow(1.1 /255, data.gamma);
+#        else
+             pow(1.0 /255, data.gamma);
+#        endif
      }
   }

@@ -7865,7 +7876,7 @@ gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
   standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
 }

-static void
+static void PNGCBAPI
 gamma_info(png_structp pp, png_infop pi)
 {
   gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
@@ -8829,7 +8840,7 @@ gamma_image_validate(gamma_display *dp, png_const_structp pp,
   dp->this.ps->validated = 1;
 }

-static void
+static void PNGCBAPI
 gamma_end(png_structp ppIn, png_infop pi)
 {
   png_const_structp pp = ppIn;
@@ -10094,12 +10105,12 @@ int main(int argc, char **argv)

   /* Store the test gammas */
   pm.gammas = gammas;
-   pm.ngammas = (sizeof gammas) / (sizeof gammas[0]);
+   pm.ngammas = ARRAY_SIZE(gammas);
   pm.ngamma_tests = 0; /* default to off */

   /* And the test encodings */
   pm.encodings = test_encodings;
-   pm.nencodings = (sizeof test_encodings) / (sizeof test_encodings[0]);
+   pm.nencodings = ARRAY_SIZE(test_encodings);

   pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */

--- a/contrib/pngminim/decoder/makefile
+++ b/contrib/pngminim/decoder/makefile
@@ -82,7 +82,7 @@ OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)

 # note: dependencies do not work on implicit rule lines
 .c$(O):
-	$(CC) $(CPPFLAGS) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<

 # dependencies

--- a/contrib/pngminim/decoder/pngusr.h
+++ b/contrib/pngminim/decoder/pngusr.h
@@ -18,7 +18,6 @@
 * affect the API (so are not recorded in pnglibconf.h)
 */

-#define PNG_NO_WARNINGS
 #define PNG_ALIGN_TYPE PNG_ALIGN_NONE

 #endif /* MINRDPNGCONF_H */
--- a/contrib/pngminim/encoder/makefile
+++ b/contrib/pngminim/encoder/makefile
@@ -81,7 +81,7 @@ OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
 # implicit make rules -------------------------------------------------------

 .c$(O):
-	$(CC) $(CPPFLAGS) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<

 # dependencies

--- a/contrib/pngminim/encoder/pngusr.h
+++ b/contrib/pngminim/encoder/pngusr.h
@@ -18,7 +18,6 @@
 * affect the API (so are not recorded in pnglibconf.h)
 */

-#define PNG_NO_WARNINGS
 #define PNG_ALIGN_TYPE PNG_ALIGN_NONE

 #endif /* MINWRPNGCONF_H */
--- a/contrib/pngminim/preader/makefile
+++ b/contrib/pngminim/preader/makefile
@@ -97,7 +97,7 @@ OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
 # implicit make rules -------------------------------------------------------

 .c$(O):
-	$(CC) $(CPPFLAGS) -c $(CFLAGS) $<
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<

 # dependencies

--- a/contrib/pngminim/preader/pngusr.h
+++ b/contrib/pngminim/preader/pngusr.h
@@ -18,7 +18,6 @@
 * affect the API (so are not recorded in pnglibconf.h)
 */

-#define PNG_NO_WARNINGS
 #define PNG_ALIGN_TYPE PNG_ALIGN_NONE

 #endif /* MINPRDPNGCONF_H */
--- a/contrib/pngminus/makefile.std
+++ b/contrib/pngminus/makefile.std
@@ -23,7 +23,8 @@ ZINC = -I../../../zlib
 ZLIB = -L../../../zlib -lz
 ZLIBS = ../../../zlib/libz.a

-CFLAGS=$(PNGINC) $(ZINC)
+CPPFLAGS=$(PNGINC) $(ZINC)
+CFLAGS=
 LDLIBS=$(PNGLIB) $(ZLIB)
 LDLIBSS=$(PNGLIBS) $(ZLIBS)
 C=.c
@@ -37,7 +38,7 @@ E=
 all: png2pnm$(E) pnm2png$(E) png2pnm-static$(E) pnm2png-static$(E)

 png2pnm$(O): png2pnm$(C)
-	$(CC) -c $(CFLAGS) png2pnm$(C)
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) png2pnm$(C)

 png2pnm$(E): png2pnm$(O)
 	$(LD) $(LDFLAGS) -o png2pnm$(E) png2pnm$(O) $(LDLIBS) -lm
@@ -46,7 +47,7 @@ png2pnm-static$(E): png2pnm$(O)
 	$(LD) $(LDFLAGS) -o png2pnm-static$(E) png2pnm$(O) $(LDLIBSS) -lm

 pnm2png$(O): pnm2png$(C)
-	$(CC) -c $(CFLAGS) pnm2png$(C)
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) pnm2png$(C)

 pnm2png$(E): pnm2png$(O)
 	$(LD) $(LDFLAGS) -o pnm2png$(E) pnm2png$(O) $(LDLIBS) -lm
--- a/contrib/pngminus/makefile.tc3
+++ b/contrib/pngminus/makefile.tc3
@@ -7,7 +7,8 @@ LB=tlib
 RM=del
 CP=copy
 MODEL=l
-CCFLAGS=-O -m$(MODEL) -I..\libpng -I..\zlib
+CPPFLAGS=-I..\libpng -I..\zlib
+CFLAGS=-O -m$(MODEL)
 LDFLAGS=-m$(MODEL) -L..\libpng -L..\zlib
 C=.c
 O=.obj
@@ -19,13 +20,13 @@ E=.exe
 all: png2pnm$(E) pnm2png$(E)

 png2pnm$(O): png2pnm$(C)
-        $(CC) -c $(CCFLAGS) png2pnm$(C)
+        $(CC) -c $(CPPFLAGS) $(CFLAGS) png2pnm$(C)

 png2pnm$(E): png2pnm$(O)
        $(LD) $(LDFLAGS) png2pnm$(O) libpng$(L) zlib$(L)

 pnm2png$(O): pnm2png$(C)
-        $(CC) -c $(CCFLAGS) pnm2png$(C)
+        $(CC) -c $(CPPFLAGS) $(CFLAGS) pnm2png$(C)

 pnm2png$(E): pnm2png$(O)
        $(LD) $(LDFLAGS) pnm2png$(O) libpng$(L) zlib$(L)
@@ -35,4 +36,3 @@ clean:
        $(RM) *$(E)

 # End of makefile for png2pnm / pnm2png
-
--- a/contrib/pngminus/png2pnm.bat
+++ b/contrib/pngminus/png2pnm.bat
--- a/contrib/pngminus/png2pnm.c
+++ b/contrib/pngminus/png2pnm.c
@@ -52,7 +52,8 @@

 int  main (int argc, char *argv[]);
 void usage ();
-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha);
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw,
+   BOOL alpha);

 /*
 *  main
@@ -85,7 +86,8 @@ int main(int argc, char *argv[])
          if ((fp_al = fopen (argv[argi], "wb")) == NULL)
          {
            fprintf (stderr, "PNM2PNG\n");
-            fprintf (stderr, "Error:  can not create alpha-channel file %s\n", argv[argi]);
+            fprintf (stderr, "Error:  can not create alpha-channel file %s\n",
+               argv[argi]);
            exit (1);
          }
          break;
@@ -176,9 +178,11 @@ void usage()
  fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
  fprintf (stderr, "   or:  ... | png2pnm [options]\n");
  fprintf (stderr, "Options:\n");
-  fprintf (stderr, "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
+  fprintf (stderr,
+     "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
  fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
+  fprintf (stderr,
+     "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
  fprintf (stderr, "   -h | -?  print this help-information\n");
 }

@@ -186,7 +190,8 @@ void usage()
 *  png2pnm
 */

-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha)
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
+    volatile BOOL raw, BOOL alpha)
 {
  png_struct    *png_ptr = NULL;
  png_info        *info_ptr = NULL;
@@ -218,7 +223,7 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a

  /* create png and info structures */

-  png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING,
+  png_ptr = png_create_read_struct (png_get_libpng_ver(NULL),
    NULL, NULL, NULL);
  if (!png_ptr)
    return FALSE;   /* out of memory */
@@ -315,12 +320,14 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
  /* row_bytes is the width x number of channels x (bit-depth / 8) */
  row_bytes = png_get_rowbytes (png_ptr, info_ptr);

-  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
+  if ((png_pixels = (png_byte *)
+     malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
    return FALSE;
  }

-  if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+  if ((row_pointers = (png_byte **)
+     malloc (height * sizeof (png_bytep))) == NULL)
  {
    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
    free (png_pixels);
@@ -329,7 +336,7 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
  }

  /* set the individual row_pointers to point at the correct offsets */
-  for (i = 0; i < (height); i++)
+  for (i = 0; i < ((int) height); i++)
    row_pointers[i] = png_pixels + i * row_bytes;

  /* now we can go ahead and just read the whole image */
@@ -372,9 +379,9 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
  /* write data to PNM file */
  pix_ptr = png_pixels;

-  for (row = 0; row < height; row++)
+  for (row = 0; row < (int) height; row++)
  {
-    for (col = 0; col < width; col++)
+    for (col = 0; col < (int) width; col++)
    {
      for (i = 0; i < (channels - alpha_present); i++)
      {
--- a/contrib/pngminus/png2pnm.sh
+++ b/contrib/pngminus/png2pnm.sh
--- a/contrib/pngminus/pngminus.bat
+++ b/contrib/pngminus/pngminus.bat
--- a/contrib/pngminus/pngminus.sh
+++ b/contrib/pngminus/pngminus.sh
--- a/contrib/pngminus/pnm2png.bat
+++ b/contrib/pngminus/pnm2png.bat
--- a/contrib/pngminus/pnm2png.c
+++ b/contrib/pngminus/pnm2png.c
@@ -50,7 +50,8 @@

 int  main (int argc, char *argv[]);
 void usage ();
-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha);
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
+    BOOL alpha);
 void get_token(FILE *pnm_file, char *token);
 png_uint_32 get_data (FILE *pnm_file, int depth);
 png_uint_32 get_value (FILE *pnm_file, int depth);
@@ -176,7 +177,8 @@ void usage()
  fprintf (stderr, "   or:  ... | pnm2png [options]\n");
  fprintf (stderr, "Options:\n");
  fprintf (stderr, "   -i[nterlace]   write png-file with interlacing on\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
+  fprintf (stderr,
+      "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
  fprintf (stderr, "   -h | -?  print this help-information\n");
 }

@@ -184,27 +186,28 @@ void usage()
 *  pnm2png
 */

-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha)
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
+     BOOL alpha)
 {
  png_struct    *png_ptr = NULL;
  png_info      *info_ptr = NULL;
  png_byte      *png_pixels = NULL;
  png_byte      **row_pointers = NULL;
  png_byte      *pix_ptr = NULL;
-  png_uint_32   row_bytes;
+  volatile png_uint_32   row_bytes;

  char          type_token[16];
  char          width_token[16];
  char          height_token[16];
  char          maxval_token[16];
-  int           color_type;
+  volatile int           color_type;
  unsigned long   ul_width=0, ul_alpha_width=0;
  unsigned long   ul_height=0, ul_alpha_height=0;
  unsigned long   ul_maxval=0;
-  png_uint_32   width, alpha_width;
-  png_uint_32   height, alpha_height;
+  volatile png_uint_32   width, height;
+  volatile png_uint_32   alpha_width, alpha_height;
  png_uint_32   maxval;
-  int           bit_depth = 0;
+  volatile int           bit_depth = 0;
  int           channels;
  int           alpha_depth = 0;
  int           alpha_present;
@@ -367,23 +370,24 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
    /* row_bytes is the width x number of channels x (bit-depth / 8) */
    row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);

-  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL)
+  if ((png_pixels = (png_byte *)
+     malloc (row_bytes * height * sizeof (png_byte))) == NULL)
    return FALSE;

  /* read data from PNM file */
  pix_ptr = png_pixels;

-  for (row = 0; row < height; row++)
+  for (row = 0; row < (int) height; row++)
  {
 #if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
    if (packed_bitmap) {
-      for (i = 0; i < row_bytes; i++)
+      for (i = 0; i < (int) row_bytes; i++)
        /* png supports this format natively so no conversion is needed */
        *pix_ptr++ = get_data (pnm_file, 8);
    } else
 #endif
    {
-      for (col = 0; col < width; col++)
+      for (col = 0; col < (int) width; col++)
      {
        for (i = 0; i < (channels - alpha_present); i++)
        {
@@ -421,7 +425,8 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  } /* end for row */

  /* prepare the standard PNG structures */
-  png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+  png_ptr = png_create_write_struct (png_get_libpng_ver(NULL), NULL, NULL,
+      NULL);
  if (!png_ptr)
  {
    return FALSE;
@@ -462,7 +467,8 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  /* if needed we will allocate memory for an new array of row-pointers */
  if (row_pointers == (unsigned char**) NULL)
  {
-    if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+    if ((row_pointers = (png_byte **)
+        malloc (height * sizeof (png_bytep))) == NULL)
    {
      png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
      return FALSE;
@@ -470,13 +476,13 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  }

  /* set the individual row_pointers to point at the correct offsets */
-  for (i = 0; i < (height); i++)
+  for (i = 0; i < (int) height; i++)
    row_pointers[i] = png_pixels + i * row_bytes;

  /* write out the entire image data in one call */
  png_write_image (png_ptr, row_pointers);

-  /* write the additional chuncks to the PNG file (not really needed) */
+  /* write the additional chunks to the PNG file (not really needed) */
  png_write_end (png_ptr, info_ptr);

  /* clean up after the write, and free any memory allocated */
--- a/contrib/pngminus/pnm2png.sh
+++ b/contrib/pngminus/pnm2png.sh
--- a/contrib/tools/intgamma.sh
+++ b/contrib/tools/intgamma.sh
--- a/contrib/tools/pngfix.c
+++ b/contrib/tools/pngfix.c
@@ -2,7 +2,7 @@
 *
 * Copyright (c) 2014 John Cunningham Bowler
 *
- * Last changed in libpng 1.6.9 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.14 [October 23, 2014]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -49,6 +49,9 @@
 #  error "pngfix will not work with libpng prior to 1.6.3"
 #endif

+#ifdef PNG_SETJMP_SUPPORTED
+#include <setjmp.h>
+
 #if defined(PNG_READ_SUPPORTED) && defined(PNG_EASY_ACCESS_SUPPORTED)
 /* zlib.h defines the structure z_stream, an instance of which is included
 * in this structure and is required for decompressing the LZ compressed
@@ -79,7 +82,7 @@
 #  error "pngfix not supported in this libpng version"
 #endif

-#if PNG_ZLIB_VERNUM >= 0x1240
+#if ZLIB_VERNUM >= 0x1240

 /* Copied from pngpriv.h */
 #ifdef __cplusplus
@@ -3159,13 +3162,13 @@ read_chunk(struct file *file)
 /* This returns a file* from a png_struct in an implementation specific way. */
 static struct file *get_control(png_const_structrp png_ptr);

-static void
+static void PNGCBAPI
 error_handler(png_structp png_ptr, png_const_charp message)
 {
   stop(get_control(png_ptr),  LIBPNG_ERROR_CODE, message);
 }

-static void
+static void PNGCBAPI
 warning_handler(png_structp png_ptr, png_const_charp message)
 {
   struct file *file = get_control(png_ptr);
@@ -3177,7 +3180,7 @@ warning_handler(png_structp png_ptr, png_const_charp message)
 /* Read callback - this is where the work gets done to check the stream before
 * passing it to libpng
 */
-static void
+static void PNGCBAPI
 read_callback(png_structp png_ptr, png_bytep buffer, size_t count)
   /* Return 'count' bytes to libpng in 'buffer' */
 {
@@ -3577,7 +3580,7 @@ read_png(struct control *control)
   volatile png_bytep row = NULL, display = NULL;
   volatile int rc;

-   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, control,
+   png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), control,
      error_handler, warning_handler);

   if (png_ptr == NULL)
@@ -4014,16 +4017,16 @@ main(int argc, const char **argv)
   return global_end(&global);
 }

-#else /* PNG_ZLIB_VERNUM < 0x1240 */
+#else /* ZLIB_VERNUM < 0x1240 */
 int
 main(void)
 {
   fprintf(stderr,
      "pngfix needs libpng with a zlib >=1.2.4 (not 0x%x)\n",
-      PNG_ZLIB_VERNUM);
+      ZLIB_VERNUM);
   return 77;
 }
-#endif /* PNG_ZLIB_VERNUM */
+#endif /* ZLIB_VERNUM */

 #else /* No read support */

@@ -4034,3 +4037,12 @@ main(void)
   return 77;
 }
 #endif /* PNG_READ_SUPPORTED && PNG_EASY_ACCESS_SUPPORTED */
+#else /* No setjmp support */
+int
+main(void)
+{
+   fprintf(stderr, "pngfix does not work without setjmp support\n");
+   return 77;
+}
+#endif /* PNG_SETJMP_SUPPORTED */
+
--- a/contrib/visupng/PngFile.c
+++ b/contrib/visupng/PngFile.c
@@ -136,7 +136,7 @@ BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,

    /* create the two png(-info) structures */

-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), NULL,
      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
    if (!png_ptr)
    {
@@ -313,7 +313,7 @@ BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,

    /* prepare the standard PNG structures */

-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
+    png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), NULL,
      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
    if (!png_ptr)
    {
--- a/example.c
+++ b/example.c
@@ -2,8 +2,8 @@
 #if 0 /* in case someone actually tries to compile this */

 /* example.c - an example of using libpng
- * Last changed in libpng 1.6.3 [July 18, 2013]
- * Maintained 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Maintained 1998-2014 Glenn Randers-Pehrson
 * Maintained 1996, 1997 Andreas Dilger)
 * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 * To the extent possible under law, the authors have waived
@@ -52,7 +52,7 @@ int main(int argc, const char **argv)
      image.version = PNG_IMAGE_VERSION;

      /* The first argument is the file to read: */
-      if (png_image_begin_read_from_file(&image, argv[1]))
+      if (png_image_begin_read_from_file(&image, argv[1]) != 0)
      {
         png_bytep buffer;

@@ -97,7 +97,7 @@ int main(int argc, const char **argv)
          */
         if (buffer != NULL &&
            png_image_finish_read(&image, NULL/*background*/, buffer,
-               0/*row_stride*/, NULL/*colormap*/))
+               0/*row_stride*/, NULL/*colormap*/) != 0)
         {
            /* Now write the image out to the second argument.  In the write
             * call 'convert_to_8bit' allows 16-bit data to be squashed down to
@@ -105,7 +105,7 @@ int main(int argc, const char **argv)
             * to the 8-bit format.
             */
            if (png_image_write_to_file(&image, argv[2], 0/*convert_to_8bit*/,
-               buffer, 0/*row_stride*/, NULL/*colormap*/))
+               buffer, 0/*row_stride*/, NULL/*colormap*/) != 0)
            {
               /* The image has been written successfully. */
               exit(0);
@@ -188,13 +188,13 @@ int main(int argc, const char **argv)
 *
 * Don't repeatedly convert between the 8-bit and 16-bit forms.  There is
 * significant data loss when 16-bit data is converted to the 8-bit encoding and
- * the current libpng implementation of convertion to 16-bit is also
+ * the current libpng implementation of conversion to 16-bit is also
 * significantly lossy.  The latter will be fixed in the future, but the former
 * is unavoidable - the 8-bit format just doesn't have enough resolution.
 */

 /* If your program needs more information from the PNG data it reads, or if you
- * need to do more complex transformations, or minimise transformations, on the
+ * need to do more complex transformations, or minimize transformations, on the
 * data you read, then you must use one of the several lower level libpng
 * interfaces.
 *
@@ -405,7 +405,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   /* Expand paletted or RGB images with transparency to full alpha channels
    * so the data will be available as RGBA quartets.
    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) != 0)
      png_set_tRNS_to_alpha(png_ptr);

   /* Set the background color to draw transparent and alpha images over.
@@ -417,7 +417,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */

   png_color_16 my_background, *image_background;

-   if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+   if (png_get_bKGD(png_ptr, info_ptr, &image_background) != 0)
      png_set_background(png_ptr, image_background,
                         PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
   else
@@ -454,12 +454,12 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */

   int intent;

-   if (png_get_sRGB(png_ptr, info_ptr, &intent))
+   if (png_get_sRGB(png_ptr, info_ptr, &intent) != 0)
      png_set_gamma(png_ptr, screen_gamma, PNG_DEFAULT_sRGB);
   else
   {
      double image_gamma;
-      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
+      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma) != 0)
         png_set_gamma(png_ptr, screen_gamma, image_gamma);
      else
         png_set_gamma(png_ptr, screen_gamma, 0.45455);
@@ -469,7 +469,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   /* Quantize RGB files down to 8 bit palette or reduce palettes
    * to the number of colors available on your screen.
    */
-   if (color_type & PNG_COLOR_MASK_COLOR)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      int num_palette;
      png_colorp palette;
@@ -484,7 +484,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
            MAX_SCREEN_COLORS, NULL, 0);
      }
      /* This reduces the image to the palette supplied in the file */
-      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
+      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) != 0)
      {
         png_uint_16p histogram = NULL;

@@ -494,7 +494,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
                        max_screen_colors, histogram, 0);
      }
   }
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
+#endif /* READ_QUANTIZE */

   /* Invert monochrome files to have 0 as white and 1 as black */
   png_set_invert_mono(png_ptr);
@@ -503,7 +503,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
    * [0,65535] to the original [0,7] or [0,31], or whatever range the
    * colors were originally in:
    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT) != 0)
   {
      png_color_8p sig_bit_p;

@@ -512,7 +512,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   }

   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
-   if (color_type & PNG_COLOR_MASK_COLOR)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
      png_set_bgr(png_ptr);

   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
@@ -532,7 +532,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   number_passes = png_set_interlace_handling(png_ptr);
 #else
   number_passes = 1;
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
+#endif /* READ_INTERLACING */


   /* Optional call to gamma correct and add the background to the palette
@@ -744,7 +744,7 @@ row_callback(png_structp png_ptr, png_bytep new_row,
    * to pass the current row as new_row, and the function will combine
    * the old row and the new row.
    */
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
+#endif /* READ_INTERLACING */
 }

 end_callback(png_structp png_ptr, png_infop info)
@@ -932,7 +932,7 @@ void write_png(char *file_name /* , ... other image information ... */)
    */

   /* Once we write out the header, the compression type on the text
-    * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
+    * chunk gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
    * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
    * at the end.
    */
@@ -970,7 +970,7 @@ void write_png(char *file_name /* , ... other image information ... */)
   png_set_packswap(png_ptr);

   /* Turn on interlace handling if you are not using png_write_image() */
-   if (interlacing)
+   if (interlacing != 0)
      number_passes = png_set_interlace_handling(png_ptr);

   else
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1,9 +1,9 @@
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.9beta02 - January 1, 2014
+ libpng version 1.6.15 - November 20, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
- Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ Copyright (c) 1998-2014 Glenn Randers-Pehrson

 This document is released under the libpng license.
 For conditions of distribution and use, see the disclaimer
@@ -11,15 +11,15 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.9beta02 - January 1, 2014
+ libpng versions 0.97, January 1998, through 1.6.15 - November 20, 2014
 Updated and distributed by Glenn Randers-Pehrson
- Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ Copyright (c) 1998-2014 Glenn Randers-Pehrson

- libpng 1.0 beta 6  version 0.96 May 28, 1997
+ libpng 1.0 beta 6 - version 0.96 - May 28, 1997
 Updated and distributed by Andreas Dilger
 Copyright (c) 1996, 1997 Andreas Dilger

- libpng 1.0 beta 2 - version 0.88  January 26, 1996
+ libpng 1.0 beta 2 - version 0.88 - January 26, 1996
 For conditions of distribution and use, see copyright
 notice in png.h. Copyright (c) 1995, 1996 Guy Eric
 Schalnat, Group 42, Inc.
@@ -54,7 +54,7 @@ This file describes how to use and modify the PNG reference library
 file, example.c is a good starting point for using the library, as
 it is heavily commented and should include everything most people
 will need.  We assume that libpng is already installed; see the
-INSTALL file for instructions on how to install libpng.
+INSTALL file for instructions on how to configure and install libpng.

 For examples of libpng usage, see the files "example.c", "pngtest.c",
 and the files in the "contrib" directory, all of which are included in
@@ -274,10 +274,10 @@ This method of building a customized pnglibconf.h is illustrated in
 contrib/pngminim/*.  See the "$(PNGCONF):" target in the makefile and
 pngusr.dfa in these directories.

-C. Configuration using PNG_USR_CONFIG
+C. Configuration using PNG_USER_CONFIG

-If -DPNG_USR_CONFIG is added to the CFLAGS when pnglibconf.h is built the file
-pngusr.h will automatically be included before the options in
+If -DPNG_USER_CONFIG is added to the CPPFLAGS when pnglibconf.h is built,
+the file pngusr.h will automatically be included before the options in
 scripts/pnglibconf.dfa are processed.  Your pngusr.h file should contain only
 macro definitions turning features on or off or setting settings.

@@ -712,12 +712,12 @@ value.  You can also specify a default encoding for the PNG file in
 case the required information is missing from the file.  By default libpng
 assumes that the PNG data matches your system, to keep this default call:

-   png_set_gamma(png_ptr, screen_gamma, 1/screen_gamma/*file gamma*/);
+   png_set_gamma(png_ptr, screen_gamma, output_gamma);

 or you can use the fixed point equivalent:

   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma,
-      PNG_FP_1/screen_gamma);
+      PNG_FP_1*output_gamma);

 If you don't know the gamma for your system it is probably 2.2 - a good
 approximation to the IEC standard for display systems (sRGB).  If images are
@@ -745,6 +745,70 @@ component value whenever arithmetic is performed.  A lot of graphics software
 uses linear values for this reason, often with higher precision component values
 to preserve overall accuracy.

+
+The output_gamma value expresses how to decode the output values, not how
+they are encoded.  The values used correspond to the normal numbers used to
+describe the overall gamma of a computer display system; for example 2.2 for
+an sRGB conformant system.  The values are scaled by 100000 in the _fixed
+version of the API (so 220000 for sRGB.)
+
+The inverse of the value is always used to provide a default for the PNG file
+encoding if it has no gAMA chunk and if png_set_gamma() has not been called
+to override the PNG gamma information.
+
+When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
+opaque pixels however pixels with lower alpha values are not encoded,
+regardless of the output gamma setting.
+
+When the standard Porter Duff handling is requested with mode 1 the output
+encoding is set to be linear and the output_gamma value is only relevant
+as a default for input data that has no gamma information.  The linear output
+encoding will be overridden if png_set_gamma() is called - the results may be
+highly unexpected!
+
+The following numbers are derived from the sRGB standard and the research
+behind it.  sRGB is defined to be approximated by a PNG gAMA chunk value of
+0.45455 (1/2.2) for PNG.  The value implicitly includes any viewing
+correction required to take account of any differences in the color
+environment of the original scene and the intended display environment; the
+value expresses how to *decode* the image for display, not how the original
+data was *encoded*.
+
+sRGB provides a peg for the PNG standard by defining a viewing environment.
+sRGB itself, and earlier TV standards, actually use a more complex transform
+(a linear portion then a gamma 2.4 power law) than PNG can express.  (PNG is
+limited to simple power laws.)  By saying that an image for direct display on
+an sRGB conformant system should be stored with a gAMA chunk value of 45455
+(11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
+makes it possible to derive values for other display systems and
+environments.
+
+The Mac value is deduced from the sRGB based on an assumption that the actual
+extra viewing correction used in early Mac display systems was implemented as
+a power 1.45 lookup table.
+
+Any system where a programmable lookup table is used or where the behavior of
+the final display device characteristics can be changed requires system
+specific code to obtain the current characteristic.  However this can be
+difficult and most PNG gamma correction only requires an approximate value.
+
+By default, if png_set_alpha_mode() is not called, libpng assumes that all
+values are unencoded, linear, values and that the output device also has a
+linear characteristic.  This is only very rarely correct - it is invariably
+better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
+default if you don't know what the right answer is!
+
+The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
+10.6) which used a correction table to implement a somewhat lower gamma on an
+otherwise sRGB system.
+
+Both these values are reserved (not simple gamma values) in order to allow
+more precise correction internally in the future.
+
+NOTE: the values can be passed to either the fixed or floating
+point APIs, but the floating point API will also accept floating point
+values.
+
 The second thing you may need to tell libpng about is how your system handles
 alpha channel information.  Some, but not all, PNG files contain an alpha
 channel.  To display these files correctly you need to compose the data onto a
@@ -769,11 +833,11 @@ by png_set_alpha_mode().

 The mode is as follows:

-    PNG_ALPHA_PNG: The data is encoded according to the PNG specification.  Red,
-green and blue, or gray, components are gamma encoded color
-values and are not premultiplied by the alpha value.  The
-alpha value is a linear measure of the contribution of the
-pixel to the corresponding final output pixel.
+    PNG_ALPHA_PNG: The data is encoded according to the PNG
+specification.  Red, green and blue, or gray, components are
+gamma encoded color values and are not premultiplied by the
+alpha value.  The alpha value is a linear measure of the
+contribution of the pixel to the corresponding final output pixel.

 You should normally use this format if you intend to perform
 color correction on the color values; most, maybe all, color
@@ -790,11 +854,35 @@ be used!

 The remaining modes assume you don't need to do any further color correction or
 that if you do, your color correction software knows all about alpha (it
-probably doesn't!)
+probably doesn't!).  They 'associate' the alpha with the color information by
+storing color channel values that have been scaled by the alpha.  The
+advantage is that the color channels can be resampled (the image can be
+scaled) in this form.  The disadvantage is that normal practice is to store
+linear, not (gamma) encoded, values and this requires 16-bit channels for
+still images rather than the 8-bit channels that are just about sufficient if
+gamma encoding is used.  In addition all non-transparent pixel values,
+including completely opaque ones, must be gamma encoded to produce the final
+image.  These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+described below (the latter being the two common names for associated alpha
+color channels). Note that PNG files always contain non-associated color
+channels; png_set_alpha_mode() with one of the modes causes the decoder to
+convert the pixels to an associated form before returning them to your
+application. 

-    PNG_ALPHA_STANDARD:  The data libpng produces
-is encoded in the standard way
-assumed by most correctly written graphics software.
+Since it is not necessary to perform arithmetic on opaque color values so
+long as they are not to be resampled and are in the final color space it is
+possible to optimize the handling of alpha by storing the opaque pixels in
+the PNG format (adjusted for the output color space) while storing partially
+opaque pixels in the standard, linear, format.  The accuracy required for
+standard alpha composition is relatively low, because the pixels are
+isolated, therefore typically the accuracy loss in storing 8-bit linear
+values is acceptable.  (This is not true if the alpha channel is used to
+simulate transparency over large areas - use 16 bits or the PNG mode in
+this case!)  This is the 'OPTIMIZED' mode.  For this mode a pixel is
+treated as opaque only if the alpha value is equal to the maximum value.
+
+    PNG_ALPHA_STANDARD:  The data libpng produces is encoded in the
+standard way assumed by most correctly written graphics software.
 The gamma encoding will be removed by libpng and the
 linear component values will be pre-multiplied by the
 alpha channel.
@@ -823,9 +911,8 @@ dynamic range.  To avoid problems, and if your software
 supports it, use png_set_expand_16() to force all
 components to 16 bits.

-    PNG_ALPHA_OPTIMIZED: This mode is the same
-as PNG_ALPHA_STANDARD except that
-completely opaque pixels are gamma encoded according to
+    PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD
+except that completely opaque pixels are gamma encoded according to
 the screen_gamma value.  Pixels with alpha less than 1.0
 will still have linear components.

@@ -844,18 +931,16 @@ representation of non-opaque pixels are irrelevant.
 You can also try this format if your software is broken;
 it might look better.

-    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD;
-however, all component values,
-including the alpha channel are gamma encoded.  This is
-an appropriate format to try if your software, or more
-likely hardware, is totally broken, i.e., if it performs
-linear arithmetic directly on gamma encoded values.
-
-In most cases of broken software or hardware the bug in the final display
-manifests as a subtle halo around composited parts of the image.  You may not
-even perceive this as a halo; the composited part of the image may simply appear
-separate from the background, as though it had been cut out of paper and pasted
-on afterward.
+    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD; however, all component
+values, including the alpha channel are gamma encoded.  This is
+broken because, in practice, no implementation that uses this choice
+correctly undoes the encoding before handling alpha composition.  Use this
+choice only if other serious errors in the software or hardware you use
+mandate it.  In most cases of broken software or hardware the bug in the
+final display manifests as a subtle halo around composited parts of the
+image.  You may not even perceive this as a halo; the composited part of
+the image may simply appear separate from the background, as though it had
+been cut out of paper and pasted on afterward.

 If you don't have to deal with bugs in software or hardware, or if you can fix
 them, there are three recommended ways of using png_set_alpha_mode():
@@ -886,6 +971,89 @@ All you can do is compose the result onto a matching output.  Since this
 mode is libpng-specific you also need to write your own composition
 software.

+The following are examples of calls to png_set_alpha_mode to achieve the
+required overall gamma correction and, where necessary, alpha
+premultiplication.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+
+This is the default libpng handling of the alpha channel - it is not
+pre-multiplied into the color components.  In addition the call states
+that the output is for a sRGB system and causes all PNG files without gAMA
+chunks to be assumed to be encoded using sRGB.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+In this case the output is assumed to be something like an sRGB conformant
+display preceeded by a power-law lookup table of power 1.45.  This is how
+early Mac systems behaved.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+
+This is the classic Jim Blinn approach and will work in academic
+environments where everything is done by the book.  It has the shortcoming
+of assuming that input PNG data with no gamma information is linear - this
+is unlikely to be correct unless the PNG files where generated locally.
+Most of the time the output precision will be so low as to show
+significant banding in dark areas of the image.
+
+    png_set_expand_16(pp);
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+
+This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
+are assumed to have the sRGB encoding if not marked with a gamma value and
+the output is always 16 bits per component.  This permits accurate scaling
+and processing of the data.  If you know that your input PNG files were
+generated locally you might need to replace PNG_DEFAULT_sRGB with the
+correct value for your system.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+
+If you just need to composite the PNG image onto an existing background
+and if you control the code that does this you can use the optimization
+setting.  In this case you just copy completely opaque pixels to the
+output.  For pixels that are not completely transparent (you just skip
+those) you do the composition math using png_composite or png_composite_16
+below then encode the resultant 8-bit or 16-bit values to match the output
+encoding.
+
+    Other cases
+
+If neither the PNG nor the standard linear encoding work for you because
+of the software or hardware you use then you have a big problem.  The PNG
+case will probably result in halos around the image.  The linear encoding
+will probably result in a washed out, too bright, image (it's actually too
+contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
+substantially reduce the halos.  Alternatively try:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+
+This option will also reduce the halos, but there will be slight dark
+halos round the opaque parts of the image where the background is light.
+In the OPTIMIZED mode the halos will be light halos where the background
+is dark.  Take your pick - the halos are unavoidable unless you can get
+your hardware/software fixed!  (The OPTIMIZED approach is slightly
+faster.)
+
+When the default gamma of PNG files doesn't match the output gamma.
+If you have PNG files with no gamma information png_set_alpha_mode allows
+you to provide a default gamma, but it also sets the ouput gamma to the
+matching value.  If you know your PNG files have a gamma that doesn't
+match the output you can take advantage of the fact that
+png_set_alpha_mode always sets the output gamma but only sets the PNG
+default if it is not already set:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+The first call sets both the default and the output gamma values, the
+second call overrides the output gamma without changing the default.  This
+is easier than achieving the same effect with png_set_gamma.  You must use
+PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+fire if more than one call to png_set_alpha_mode and png_set_background is
+made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+are ignored.
+
 If you don't need, or can't handle, the alpha channel you can call
 png_set_background() to remove it by compositing against a fixed color.  Don't
 call png_set_strip_alpha() to do this - it will leave spurious pixel values in
@@ -1216,7 +1384,7 @@ png_set_rgb_to_gray()).

    png_get_sRGB(png_ptr, info_ptr, &srgb_intent);

-    file_srgb_intent - the rendering intent (PNG_INFO_sRGB)
+    srgb_intent -    the rendering intent (PNG_INFO_sRGB)
                     The presence of the sRGB chunk
                     means that the pixel data is in the
                     sRGB color space.  This chunk also
@@ -2166,10 +2334,15 @@ how pngvalid.c does it.
 Finishing a sequential read

 After you are finished reading the image through the
-low-level interface, you can finish reading the file.  If you are
-interested in comments or time, which may be stored either before or
-after the image data, you should pass the separate png_info struct if
-you want to keep the comments from before and after the image
+low-level interface, you can finish reading the file.
+
+If you want to use a different crc action for handling CRC errors in
+chunks after the image data, you can call png_set_crc_action()
+again at this point.
+
+If you are interested in comments or time, which may be stored either
+before or after the image data, you should pass the separate png_info
+struct if you want to keep the comments from before and after the image
 separate.

    png_infop end_info = png_create_info_struct(png_ptr);
@@ -2185,6 +2358,9 @@ separate.

 If you are not interested, you should still call png_read_end()
 but you can pass NULL, avoiding the need to create an end_info structure.
+If you do this, libpng will not process any chunks after IDAT other than
+skipping over them and perhaps (depending on whether you have called
+png_set_crc_action) checking their CRCs while looking for the IEND chunk.

   png_read_end(png_ptr, (png_infop)NULL);

@@ -2460,7 +2636,7 @@ png_infop info_ptr;
        png_progressive_combine_row(png_ptr, old_row,
          new_row);

-    /* where old_row is what was displayed for
+    /* where old_row is what was displayed
       previously for the row.  Note that the first
       pass (pass == 0, really) will completely cover
       the old row, so the rows do not have to be
@@ -3085,7 +3261,7 @@ tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
 although this isn't a requirement.  Unlike the tIME chunk, the
 "Creation Time" tEXt chunk is not expected to be automatically changed
 by the software.  To facilitate the use of RFC 1123 dates, a function
-png_convert_to_rfc1123_buffer(png_ptr, buffer, png_timep) is provided to
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
 convert from PNG time to an RFC 1123 format string.  The caller must provide
 a writeable buffer of at least 29 bytes.

@@ -3617,8 +3793,9 @@ and matches the 8-bit format expected by typical display devices.
 The color/gray channels are not scaled (pre-multiplied) by the alpha
 channel and are suitable for passing to color management software.

-  b) As a value in the range 0..65535, contained in a 2-byte integer.  All
-channels can be converted to the original value by dividing by 65535; all
+  b) As a value in the range 0..65535, contained in a 2-byte integer, in
+the native byte order of the platform on which the application is running.
+All channels can be converted to the original value by dividing by 65535; all
 channels are linear.  Color channels use the RGB encoding (RGB end-points) of
 the sRGB specification.  This encoding is identified by the
 PNG_FORMAT_FLAG_LINEAR flag below.
@@ -3685,7 +3862,9 @@ First the single byte formats:
 Then the linear 2-byte formats.  When naming these "Y" is used to
 indicate a luminance (gray) channel.  The component order within the pixel
 is always the same - there is no provision for swapping the order of the
-components in the linear format.
+components in the linear format.  The components are 16-bit integers in
+the native byte order for your platform, and there is no provision for
+swapping the bytes to a different endian condition.

   PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
   PNG_FORMAT_LINEAR_Y_ALPHA
@@ -3750,7 +3929,7 @@ First the information about the samples.
    *
    * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
    *
-    * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+    * Alternatively, use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
    * information from one of the png_image_begin_read_ APIs and dynamically
    * allocate the required memory.
    */
@@ -3779,9 +3958,16 @@ Information about the whole row, or whole image
   row.  For a color-mapped image this is the minimum number of bytes in a
   row.

+   If you need the stride measured in bytes, row_stride_bytes is
+   PNG_IMAGE_ROW_STRIDE(image) * PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)
+   plus any padding bytes that your application might need, for example
+   to start the next row on a 4-byte boundary.
+
  PNG_IMAGE_BUFFER_SIZE(image, row_stride)
    Returns the size, in bytes, of an image buffer given a png_image and a row
-    stride - the number of components to leave space for in each row.
+    stride - the number of components to leave space for in each row.  This
+    macro takes care of multiplying row_stride by PNG_IMAGE_PIXEL_COMONENT_SIZE
+    when the image has 2-byte components.

  PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01
    This indicates the the RGB values of the in-memory bitmap do not
@@ -3910,14 +4096,11 @@ clears the newly allocated memory to zero; note that png_calloc(png_ptr, size)
 is not the same as the calloc(number, size) function provided by stdlib.h.
 There is limited support for certain systems with segmented memory
 architectures and the types of pointers declared by png.h match this; you
-will have to use appropriate pointers in your application.  Since it is
-unlikely that the method of handling memory allocation on a platform
-will change between applications, these functions must be modified in
-the library at compile time.  If you prefer to use a different method
-of allocating and freeing data, you can use png_create_read_struct_2() or
-png_create_write_struct_2() to register your own functions as described
-above.  These functions also provide a void pointer that can be retrieved
-via
+will have to use appropriate pointers in your application.  If you prefer
+to use a different method of allocating and freeing data, you can use
+png_create_read_struct_2() or png_create_write_struct_2() to register your
+own functions as described above.  These functions also provide a void
+pointer that can be retrieved via

    mem_ptr=png_get_mem_ptr(png_ptr);

@@ -4060,29 +4243,6 @@ the simpler ones to get an idea of how they work.  Try to find a similar
 transformation to the one you want to add and copy off of it.  More details
 can be found in the comments inside the code itself.

-Configuring for 16-bit platforms
-
-You will want to look into zconf.h to tell zlib (and thus libpng) that
-it cannot allocate more then 64K at a time.  Even if you can, the memory
-won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.
-
-Configuring for DOS
-
-For DOS users who only have access to the lower 640K, you will
-have to limit zlib's memory usage via a png_set_compression_mem_level()
-call.  See zlib.h or zconf.h in the zlib library for more information.
-
-Configuring for Medium Model
-
-Libpng's support for medium model has been tested on most of the popular
-compilers.  Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
-defined, and FAR gets defined to far in pngconf.h, and you should be
-all set.  Everything in the library (except for zlib's structure) is
-expecting far data.  You must use the typedefs with the p or pp on
-the end for pointers (or at least look at them and be careful).  Make
-note that the rows of data are defined as png_bytepp, which is
-an "unsigned char far * far *".
-
 Configuring for gui/windowing platforms:

 You will need to write new error and warning functions that use the GUI
@@ -4092,18 +4252,6 @@ in order to have them available during the structure initialization.
 They can be changed later via png_set_error_fn().  On some compilers,
 you may also have to change the memory allocators (png_malloc, etc.).

-Configuring for compiler xxx:
-
-All includes for libpng are in pngconf.h.  If you need to add, change
-or delete an include, this is the place to do it.
-The includes that are not needed outside libpng are placed in pngpriv.h,
-which is only used by the routines inside libpng itself.
-The files in libpng proper only include pngpriv.h and png.h, which
-in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
-As of libpng-1.5.0, pngpriv.h also includes three other private header
-files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
-that previously appeared in the public headers.
-
 Configuring zlib:

 There are special functions to configure the compression.  Perhaps the
@@ -4145,6 +4293,8 @@ zlib.h for more information on what these mean.

    png_set_compression_method(png_ptr, method);

+This controls the size of the IDAT chunks (default 8192):
+
    png_set_compression_buffer_size(png_ptr, size);

 As of libpng version 1.5.4, additional APIs became
@@ -4243,46 +4393,6 @@ Note that the numbers above were invented purely for this example and
 are given only to help explain the function usage.  Little testing has
 been done to find optimum values for either the costs or the weights.

-Removing unwanted object code
-
-There are a bunch of #define's in pngconf.h that control what parts of
-libpng are compiled.  All the defines end in _SUPPORTED.  If you are
-never going to use a capability, you can change the #define to #undef
-before recompiling libpng and save yourself code and data space, or
-you can turn off individual capabilities with defines that begin with
-PNG_NO_.
-
-In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
-
-You can also turn all of the transforms and ancillary chunk capabilities
-off en masse with compiler directives that define
-PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
-or all four,
-along with directives to turn on any of the capabilities that you do
-want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the extra
-transformations but still leave the library fully capable of reading
-and writing PNG files with all known public chunks. Use of the
-PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
-that is incapable of reading or writing ancillary chunks.  If you are
-not using the progressive reading capability, you can turn that off
-with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
-capability, which you'll still have).
-
-All the reading and writing specific code are in separate files, so the
-linker should only grab the files it needs.  However, if you want to
-make sure, or if you are building a stand alone library, all the
-reading files start with "pngr" and all the writing files start with "pngw".
-The files that don't match either (like png.c, pngtrans.c, etc.)
-are used for both reading and writing, and always need to be included.
-The progressive reader is in pngpread.c
-
-If you are creating or distributing a dynamically linked library (a .so
-or DLL file), you should not remove or disable any parts of the library,
-as this will cause applications linked with different versions of the
-library to fail if they call functions not available in your library.
-The size of the library itself should not be an issue, because only
-those sections that are actually used will be loaded into memory.
-
 Requesting debug printout

 The macro definition PNG_DEBUG can be used to request debugging
@@ -4320,17 +4430,6 @@ When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
 having level = 0 will be printed.  There aren't any such statements in
 this version of libpng, but if you insert some they will be printed.

-Prepending a prefix to exported symbols
-
-Starting with libpng-1.6.0, you can configure libpng (when using the
-"configure" script) to prefix all exported symbols by means of the
-configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any
-string beginning with a letter and containing only uppercase
-and lowercase letters, digits, and the underscore (i.e., a C language
-identifier).  This creates a set of macros in pnglibconf.h, so this is
-transparent to applications; their function calls get transformed by
-the macros to use the modified names.
-
 VII.  MNG support

 The MNG specification (available at http://www.libpng.org/pub/mng) allows
@@ -4393,6 +4492,9 @@ png_set_error_fn(), which is essentially the same function, but with a new
 name to force compilation errors with applications that try to use the old
 method.

+Support for the sCAL, iCCP, iTXt, and sPLT chunks was added at libpng-1.0.6;
+however, iTXt support was not enabled by default.
+
 Starting with version 1.0.7, you can find out which version of the library
 you are using at run-time:

@@ -4621,6 +4723,7 @@ XI.  Changes to Libpng from version 1.4.x to 1.5.x

 From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
 function) incorrectly returned a value of type png_uint_32.
+The incorrect macro was removed from libpng-1.4.5.

 Checking for invalid palette index on write was added at libpng
 1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
@@ -4653,8 +4756,6 @@ does not account for any palette index used by ancillary chunks such as the
 bKGD chunk; you must check those separately to determine the maximum
 palette index actually used.

-A. Changes that affect users of libpng
-
 There are no substantial API changes between the non-deprecated parts of
 the 1.4.5 API and the 1.5.0 API; however, the ability to directly access
 members of the main libpng control structures, png_struct and png_info,
@@ -4725,7 +4826,10 @@ and the accuracy of PNG fixed point values is insufficient for
 representation of these values. Consequently a "string" API
 (png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
 arbitrary sCAL chunks in the absence of either the floating point API or
-internal floating point calculations.
+internal floating point calculations.  Starting with libpng-1.5.0, both
+of these functions are present when PNG_sCAL_SUPPORTED is defined.  Prior
+to libpng-1.5.0, their presence also depended upon PNG_FIXED_POINT_SUPPORTED
+being defined and PNG_FLOATING_POINT_SUPPORTED not being defined.

 Applications no longer need to include the optional distribution header
 file pngusr.h or define the corresponding macros during application
@@ -4745,11 +4849,6 @@ reset by pngusr.h or by explicit settings on the compiler command line.
 These settings may produce compiler warnings or errors in 1.5.0 because
 of macro redefinition.

-From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
-function) incorrectly returned a value of type png_uint_32.  libpng 1.5.0
-is consistent with the implementation in 1.4.5 and 1.2.x (where the macro
-did not exist.)
-
 Applications can now choose whether to use these macros or to call the
 corresponding function by defining PNG_USE_READ_MACROS or
 PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
@@ -4767,7 +4866,10 @@ option was off by default, and slightly inaccurate scaling occurred.
 This option can no longer be turned off, and the choice of accurate
 or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
 API for accurate scaling or the old png_set_strip_16_to_8() API for simple
-chopping.
+chopping.  In libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+macro became PNG_READ_SCALE_16_TO_8_SUPPORTED, and the PNG_READ_16_TO_8
+macro became PNG_READ_STRIP_16_TO_8_SUPPORTED, to enable the two
+png_set_*_16_to_8() functions separately.

 Prior to libpng-1.5.4, the png_set_user_limits() function could only be
 used to reduce the width and height limits from the value of
@@ -4792,26 +4894,6 @@ limits are now
 The png_set_option() function (and the "options" member of the png struct) was
 added to libpng-1.5.15.

-B. Changes to the build and configuration of libpng
-
-Details of internal changes to the library code can be found in the CHANGES
-file and in the GIT repository logs.  These will be of no concern to the vast
-majority of library users or builders; however, the few who configure libpng
-to a non-default feature set may need to change how this is done.
-
-There should be no need for library builders to alter build scripts if
-these use the distributed build support - configure or the makefiles -
-however, users of the makefiles may care to update their build scripts
-to build pnglibconf.h where the corresponding makefile does not do so.
-
-Building libpng with a non-default configuration has changed completely.
-The old method using pngusr.h should still work correctly even though the
-way pngusr.h is used in the build has been changed; however, library
-builders will probably want to examine the changes to take advantage of
-new capabilities and to simplify their build system.
-
-B.1 Specific changes to library configuration capabilities
-
 The library now supports a complete fixed point implementation and can
 thus be used on systems that have no floating point support or very
 limited or slow support.  Previously gamma correction, an essential part
@@ -4822,27 +4904,7 @@ independent of the choice of fixed versus floating point APIs and all the
 missing fixed point APIs have been implemented.

 The exact mechanism used to control attributes of API functions has
-changed.  A single set of operating system independent macro definitions
-is used and operating system specific directives are defined in
-pnglibconf.h
-
-As part of this the mechanism used to choose procedure call standards on
-those systems that allow a choice has been changed.  At present this only
-affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
-running on Intel processors.  As before, PNGAPI is defined where required
-to control the exported API functions; however, two new macros, PNGCBAPI
-and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
-(PNGCAPI) for functions that must match a C library prototype (currently
-only png_longjmp_ptr, which must match the C longjmp function.)  The new
-approach is documented in pngconf.h
-
-Despite these changes, libpng 1.5.0 only supports the native C function
-calling standard on those platforms tested so far (__cdecl on Microsoft
-Windows).  This is because the support requirements for alternative
-calling conventions seem to no longer exist.  Developers who find it
-necessary to set PNG_API_RULE to 1 should advise the mailing list
-(png-mng-implement) of this and library builders who use Openwatcom and
-therefore set PNG_API_RULE to 2 should also contact the mailing list.
+changed, as described in the INSTALL file.

 A new test program, pngvalid, is provided in addition to pngtest.
 pngvalid validates the arithmetic accuracy of the gamma correction
@@ -4918,46 +4980,6 @@ even though the default is to use the macros - this allows applications
 to choose at app buildtime whether or not to use macros (previously
 impossible because the functions weren't in the default build.)

-B.2 Changes to the configuration mechanism
-
-Prior to libpng-1.5.0 library builders who needed to configure libpng
-had either to modify the exported pngconf.h header file to add system
-specific configuration or had to write feature selection macros into
-pngusr.h and cause this to be included into pngconf.h by defining
-PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
-application built without PNG_USER_CONFIG defined would see the
-unmodified, default, libpng API and thus would probably fail to link.
-
-These mechanisms still work in the configure build and in any makefile
-build that builds pnglibconf.h, although the feature selection macros
-have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
-processed only once, when the exported header file pnglibconf.h is built.
-pngconf.h no longer includes pngusr.h, therefore pngusr.h is ignored after the
-build of pnglibconf.h and it is never included in an application build.
-
-The rarely used alternative of adding a list of feature macros to the
-CFLAGS setting in the build also still works; however, the macros will be
-copied to pnglibconf.h and this may produce macro redefinition warnings
-when the individual C files are compiled.
-
-All configuration now only works if pnglibconf.h is built from
-scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
-(the original author of awk) maintains C source code of that awk and this
-and all known later implementations (often called by subtly different
-names - nawk and gawk for example) are adequate to build pnglibconf.h.
-The Sun Microsystems (now Oracle) program 'awk' is an earlier version
-and does not work; this may also apply to other systems that have a
-functioning awk called 'nawk'.
-
-Configuration options are now documented in scripts/pnglibconf.dfa.  This
-file also includes dependency information that ensures a configuration is
-consistent; that is, if a feature is switched off dependent features are
-also removed.  As a recommended alternative to using feature macros in
-pngusr.h a system builder may also define equivalent options in pngusr.dfa
-(or, indeed, any file) and add that to the configuration by setting
-DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
-how to do this, and a case where pngusr.h is still required.
-
 XII.  Changes to Libpng from version 1.5.x to 1.6.x

 A "simplified API" has been added (see documentation in png.h and a simple
@@ -4993,7 +5015,6 @@ The following API are now DEPRECATED:
   png_info_init_3()
   png_convert_to_rfc1123() which has been replaced
     with png_convert_to_rfc1123_buffer()
-   png_data_freer()
   png_malloc_default()
   png_free_default()
   png_reset_zstream()
@@ -5017,11 +5038,26 @@ Error detection in some chunks has improved; in particular the iCCP chunk
 reader now does pretty complete validation of the basic format.  Some bad
 profiles that were previously accepted are now accepted with a warning or
 rejected, depending upon the png_set_benign_errors() setting, in particular the
-very old broken Microsoft/HP 3144-byte sRGB profile.  The PNG spec requirement
-that only grayscale profiles may appear in images with color type 0 or 4 and
-that even if the image only contains gray pixels, only RGB profiles may appear
-in images with color type 2, 3, or 6, is now enforced.  The sRGB chunk
-is allowed to appear in images with any color type.
+very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
+libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
+means of
+
+    #if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && \
+        defined(PNG_SET_OPTION_SUPPORTED)
+       png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE,
+           PNG_OPTION_ON);
+    #endif
+
+It's not a good idea to do this if you are using the "simplified API",
+which needs to be able to recognize an sRGB profile conveyed via the iCCP
+chunk.
+
+The PNG spec requirement that only grayscale profiles may appear in images
+with color type 0 or 4 and that even if the image only contains gray pixels,
+only RGB profiles may appear in images with color type 2, 3, or 6, is now
+enforced.  The sRGB chunk is allowed to appear in images with any color type
+and is interpreted by libpng to convey a one-tracer-curve gray profile or a
+three-tracer-curve RGB profile as appropriate.

 Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
 an empty language field or an empty translated keyword.  Both of these
@@ -5055,16 +5091,16 @@ Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT
 stream to set the size of the sliding window for reading instead of using the
 default 32-kbyte sliding window size.  It was discovered that there are
 hundreds of PNG files in the wild that have incorrect CMF bytes that caused
-libpng to issue a "too far back" error and reject the file.  Libpng-1.6.3 and
-later calculate their own safe CMF from the image dimensions, provide a way
-to revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a
-32-kbyte sliding window), by using
+zlib to issue the "invalid distance too far back" error and reject the file.
+Libpng-1.6.3 and later calculate their own safe CMF from the image dimensions,
+provide a way to revert to the libpng-1.5.x behavior (ignoring the CMF bytes
+and using a 32-kbyte sliding window), by using

    png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW,
        PNG_OPTION_ON);

-and provide a tool (contrib/tools/pngfix) for optimizing the CMF bytes
-correctly.
+and provide a tool (contrib/tools/pngfix) for rewriting a PNG file while
+optimizing the CMF bytes in its IDAT chunk correctly.

 Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
 length, which resulted in PNG files that cannot be read beyond the bad iTXt
@@ -5106,7 +5142,8 @@ mailing list, or directly to glennrp.

 XV. Coding style

-Our coding style is similar to the "Allman" style, with curly
+Our coding style is similar to the "Allman" style
+(See http://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
 braces on separate lines:

    if (condition)
@@ -5169,6 +5206,9 @@ exported functions are marked with PNGAPI:
    body;
 }

+The return type and decorations are placed on a separate line
+ahead of the function name, as illustrated above.
+
 The prototypes for all exported functions appear in png.h,
 above the comment that says

@@ -5183,12 +5223,15 @@ We mark all non-exported functions with "/* PRIVATE */"":
 }

 The prototypes for non-exported functions (except for those in
-pngtest) appear in
-pngpriv.h
-above the comment that says
+pngtest) appear in pngpriv.h above the comment that says

  /* Maintainer: Put new private prototypes here ^ */

+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
 We put a space after the "sizeof" operator and we omit the
 optional parentheses around its argument when the argument
 is an expression, not a type name, and we always enclose the
@@ -5200,10 +5243,8 @@ sizeof operator, with its argument, in parentheses:
 Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
 though it were a function.

-To avoid polluting the global namespace, the names of all exported
-functions and variables begin with "png_", and all publicly visible C
-preprocessor macros begin with "PNG".  We request that applications that
-use libpng *not* begin any of their own symbols with either of these strings.
+Control keywords if, for, while, and switch are always followed by a space
+to distinguish them from function calls, which have no trailing space. 

 We put a space after each comma and after each semicolon
 in "for" statements, and we put spaces before and after each
@@ -5225,6 +5266,9 @@ with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100).
 We prefer to use underscores in variable names rather than camelCase, except
 for a few type names that we inherit from zlib.h.

+We prefer "if (something != 0)" and "if (something == 0)"
+over "if (something)" and if "(!something)", respectively.
+
 We do not use the TAB character for indentation in the C sources.

 Lines do not exceed 80 characters.
@@ -5233,13 +5277,13 @@ Other rules can be inferred by inspecting the libpng source.

 XVI. Y2K Compliance in libpng

-January 1, 2014
+November 20, 2014

 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.

 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.6.9beta02 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.15 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.

 Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -5255,8 +5299,9 @@ in libpng-1.6.x and will be removed from libpng-1.7.0.

 There are seven time-related functions:

-    png_convert_to_rfc_1123() in png.c
-      (formerly png_convert_to_rfc_1152() in error)
+    png_convert_to_rfc_1123_buffer() in png.c
+      (formerly png_convert_to_rfc_1152() in error, and
+      also formerly png_convert_to_rfc_1123())
    png_convert_from_struct_tm() in pngwrite.c, called
      in pngwrite.c
    png_convert_from_time_t() in pngwrite.c
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "January 1, 2014"
+.TH LIBPNG 3 "November 20, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.9beta02
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.15
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -504,10 +504,10 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.6.9beta02 - January 1, 2014
+ libpng version 1.6.15 - November 20, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
- Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ Copyright (c) 1998-2014 Glenn Randers-Pehrson

 This document is released under the libpng license.
 For conditions of distribution and use, see the disclaimer
@@ -515,15 +515,15 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.6.9beta02 - January 1, 2014
+ libpng versions 0.97, January 1998, through 1.6.15 - November 20, 2014
 Updated and distributed by Glenn Randers-Pehrson
- Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ Copyright (c) 1998-2014 Glenn Randers-Pehrson

- libpng 1.0 beta 6  version 0.96 May 28, 1997
+ libpng 1.0 beta 6 - version 0.96 - May 28, 1997
 Updated and distributed by Andreas Dilger
 Copyright (c) 1996, 1997 Andreas Dilger

- libpng 1.0 beta 2 - version 0.88  January 26, 1996
+ libpng 1.0 beta 2 - version 0.88 - January 26, 1996
 For conditions of distribution and use, see copyright
 notice in png.h. Copyright (c) 1995, 1996 Guy Eric
 Schalnat, Group 42, Inc.
@@ -558,7 +558,7 @@ This file describes how to use and modify the PNG reference library
 file, example.c is a good starting point for using the library, as
 it is heavily commented and should include everything most people
 will need.  We assume that libpng is already installed; see the
-INSTALL file for instructions on how to install libpng.
+INSTALL file for instructions on how to configure and install libpng.

 For examples of libpng usage, see the files "example.c", "pngtest.c",
 and the files in the "contrib" directory, all of which are included in
@@ -778,10 +778,10 @@ This method of building a customized pnglibconf.h is illustrated in
 contrib/pngminim/*.  See the "$(PNGCONF):" target in the makefile and
 pngusr.dfa in these directories.

-C. Configuration using PNG_USR_CONFIG
+C. Configuration using PNG_USER_CONFIG

-If \-DPNG_USR_CONFIG is added to the CFLAGS when pnglibconf.h is built the file
-pngusr.h will automatically be included before the options in
+If \-DPNG_USER_CONFIG is added to the CPPFLAGS when pnglibconf.h is built,
+the file pngusr.h will automatically be included before the options in
 scripts/pnglibconf.dfa are processed.  Your pngusr.h file should contain only
 macro definitions turning features on or off or setting settings.

@@ -1216,12 +1216,12 @@ value.  You can also specify a default encoding for the PNG file in
 case the required information is missing from the file.  By default libpng
 assumes that the PNG data matches your system, to keep this default call:

-   png_set_gamma(png_ptr, screen_gamma, 1/screen_gamma/*file gamma*/);
+   png_set_gamma(png_ptr, screen_gamma, output_gamma);

 or you can use the fixed point equivalent:

   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma,
-      PNG_FP_1/screen_gamma);
+      PNG_FP_1*output_gamma);

 If you don't know the gamma for your system it is probably 2.2 - a good
 approximation to the IEC standard for display systems (sRGB).  If images are
@@ -1249,6 +1249,70 @@ component value whenever arithmetic is performed.  A lot of graphics software
 uses linear values for this reason, often with higher precision component values
 to preserve overall accuracy.

+
+The output_gamma value expresses how to decode the output values, not how
+they are encoded.  The values used correspond to the normal numbers used to
+describe the overall gamma of a computer display system; for example 2.2 for
+an sRGB conformant system.  The values are scaled by 100000 in the _fixed
+version of the API (so 220000 for sRGB.)
+
+The inverse of the value is always used to provide a default for the PNG file
+encoding if it has no gAMA chunk and if png_set_gamma() has not been called
+to override the PNG gamma information.
+
+When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
+opaque pixels however pixels with lower alpha values are not encoded,
+regardless of the output gamma setting.
+
+When the standard Porter Duff handling is requested with mode 1 the output
+encoding is set to be linear and the output_gamma value is only relevant
+as a default for input data that has no gamma information.  The linear output
+encoding will be overridden if png_set_gamma() is called - the results may be
+highly unexpected!
+
+The following numbers are derived from the sRGB standard and the research
+behind it.  sRGB is defined to be approximated by a PNG gAMA chunk value of
+0.45455 (1/2.2) for PNG.  The value implicitly includes any viewing
+correction required to take account of any differences in the color
+environment of the original scene and the intended display environment; the
+value expresses how to *decode* the image for display, not how the original
+data was *encoded*.
+
+sRGB provides a peg for the PNG standard by defining a viewing environment.
+sRGB itself, and earlier TV standards, actually use a more complex transform
+(a linear portion then a gamma 2.4 power law) than PNG can express.  (PNG is
+limited to simple power laws.)  By saying that an image for direct display on
+an sRGB conformant system should be stored with a gAMA chunk value of 45455
+(11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
+makes it possible to derive values for other display systems and
+environments.
+
+The Mac value is deduced from the sRGB based on an assumption that the actual
+extra viewing correction used in early Mac display systems was implemented as
+a power 1.45 lookup table.
+
+Any system where a programmable lookup table is used or where the behavior of
+the final display device characteristics can be changed requires system
+specific code to obtain the current characteristic.  However this can be
+difficult and most PNG gamma correction only requires an approximate value.
+
+By default, if png_set_alpha_mode() is not called, libpng assumes that all
+values are unencoded, linear, values and that the output device also has a
+linear characteristic.  This is only very rarely correct - it is invariably
+better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
+default if you don't know what the right answer is!
+
+The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
+10.6) which used a correction table to implement a somewhat lower gamma on an
+otherwise sRGB system.
+
+Both these values are reserved (not simple gamma values) in order to allow
+more precise correction internally in the future.
+
+NOTE: the values can be passed to either the fixed or floating
+point APIs, but the floating point API will also accept floating point
+values.
+
 The second thing you may need to tell libpng about is how your system handles
 alpha channel information.  Some, but not all, PNG files contain an alpha
 channel.  To display these files correctly you need to compose the data onto a
@@ -1273,11 +1337,11 @@ by png_set_alpha_mode().

 The mode is as follows:

-    PNG_ALPHA_PNG: The data is encoded according to the PNG specification.  Red,
-green and blue, or gray, components are gamma encoded color
-values and are not premultiplied by the alpha value.  The
-alpha value is a linear measure of the contribution of the
-pixel to the corresponding final output pixel.
+    PNG_ALPHA_PNG: The data is encoded according to the PNG
+specification.  Red, green and blue, or gray, components are
+gamma encoded color values and are not premultiplied by the
+alpha value.  The alpha value is a linear measure of the
+contribution of the pixel to the corresponding final output pixel.

 You should normally use this format if you intend to perform
 color correction on the color values; most, maybe all, color
@@ -1294,11 +1358,35 @@ be used!

 The remaining modes assume you don't need to do any further color correction or
 that if you do, your color correction software knows all about alpha (it
-probably doesn't!)
+probably doesn't!).  They 'associate' the alpha with the color information by
+storing color channel values that have been scaled by the alpha.  The
+advantage is that the color channels can be resampled (the image can be
+scaled) in this form.  The disadvantage is that normal practice is to store
+linear, not (gamma) encoded, values and this requires 16-bit channels for
+still images rather than the 8-bit channels that are just about sufficient if
+gamma encoding is used.  In addition all non-transparent pixel values,
+including completely opaque ones, must be gamma encoded to produce the final
+image.  These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+described below (the latter being the two common names for associated alpha
+color channels). Note that PNG files always contain non-associated color
+channels; png_set_alpha_mode() with one of the modes causes the decoder to
+convert the pixels to an associated form before returning them to your
+application. 

-    PNG_ALPHA_STANDARD:  The data libpng produces
-is encoded in the standard way
-assumed by most correctly written graphics software.
+Since it is not necessary to perform arithmetic on opaque color values so
+long as they are not to be resampled and are in the final color space it is
+possible to optimize the handling of alpha by storing the opaque pixels in
+the PNG format (adjusted for the output color space) while storing partially
+opaque pixels in the standard, linear, format.  The accuracy required for
+standard alpha composition is relatively low, because the pixels are
+isolated, therefore typically the accuracy loss in storing 8-bit linear
+values is acceptable.  (This is not true if the alpha channel is used to
+simulate transparency over large areas - use 16 bits or the PNG mode in
+this case!)  This is the 'OPTIMIZED' mode.  For this mode a pixel is
+treated as opaque only if the alpha value is equal to the maximum value.
+
+    PNG_ALPHA_STANDARD:  The data libpng produces is encoded in the
+standard way assumed by most correctly written graphics software.
 The gamma encoding will be removed by libpng and the
 linear component values will be pre-multiplied by the
 alpha channel.
@@ -1327,9 +1415,8 @@ dynamic range.  To avoid problems, and if your software
 supports it, use png_set_expand_16() to force all
 components to 16 bits.

-    PNG_ALPHA_OPTIMIZED: This mode is the same
-as PNG_ALPHA_STANDARD except that
-completely opaque pixels are gamma encoded according to
+    PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD
+except that completely opaque pixels are gamma encoded according to
 the screen_gamma value.  Pixels with alpha less than 1.0
 will still have linear components.

@@ -1348,18 +1435,16 @@ representation of non-opaque pixels are irrelevant.
 You can also try this format if your software is broken;
 it might look better.

-    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD;
-however, all component values,
-including the alpha channel are gamma encoded.  This is
-an appropriate format to try if your software, or more
-likely hardware, is totally broken, i.e., if it performs
-linear arithmetic directly on gamma encoded values.
-
-In most cases of broken software or hardware the bug in the final display
-manifests as a subtle halo around composited parts of the image.  You may not
-even perceive this as a halo; the composited part of the image may simply appear
-separate from the background, as though it had been cut out of paper and pasted
-on afterward.
+    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD; however, all component
+values, including the alpha channel are gamma encoded.  This is
+broken because, in practice, no implementation that uses this choice
+correctly undoes the encoding before handling alpha composition.  Use this
+choice only if other serious errors in the software or hardware you use
+mandate it.  In most cases of broken software or hardware the bug in the
+final display manifests as a subtle halo around composited parts of the
+image.  You may not even perceive this as a halo; the composited part of
+the image may simply appear separate from the background, as though it had
+been cut out of paper and pasted on afterward.

 If you don't have to deal with bugs in software or hardware, or if you can fix
 them, there are three recommended ways of using png_set_alpha_mode():
@@ -1390,6 +1475,89 @@ All you can do is compose the result onto a matching output.  Since this
 mode is libpng-specific you also need to write your own composition
 software.

+The following are examples of calls to png_set_alpha_mode to achieve the
+required overall gamma correction and, where necessary, alpha
+premultiplication.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+
+This is the default libpng handling of the alpha channel - it is not
+pre-multiplied into the color components.  In addition the call states
+that the output is for a sRGB system and causes all PNG files without gAMA
+chunks to be assumed to be encoded using sRGB.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+In this case the output is assumed to be something like an sRGB conformant
+display preceeded by a power-law lookup table of power 1.45.  This is how
+early Mac systems behaved.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+
+This is the classic Jim Blinn approach and will work in academic
+environments where everything is done by the book.  It has the shortcoming
+of assuming that input PNG data with no gamma information is linear - this
+is unlikely to be correct unless the PNG files where generated locally.
+Most of the time the output precision will be so low as to show
+significant banding in dark areas of the image.
+
+    png_set_expand_16(pp);
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+
+This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
+are assumed to have the sRGB encoding if not marked with a gamma value and
+the output is always 16 bits per component.  This permits accurate scaling
+and processing of the data.  If you know that your input PNG files were
+generated locally you might need to replace PNG_DEFAULT_sRGB with the
+correct value for your system.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+
+If you just need to composite the PNG image onto an existing background
+and if you control the code that does this you can use the optimization
+setting.  In this case you just copy completely opaque pixels to the
+output.  For pixels that are not completely transparent (you just skip
+those) you do the composition math using png_composite or png_composite_16
+below then encode the resultant 8-bit or 16-bit values to match the output
+encoding.
+
+    Other cases
+
+If neither the PNG nor the standard linear encoding work for you because
+of the software or hardware you use then you have a big problem.  The PNG
+case will probably result in halos around the image.  The linear encoding
+will probably result in a washed out, too bright, image (it's actually too
+contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
+substantially reduce the halos.  Alternatively try:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+
+This option will also reduce the halos, but there will be slight dark
+halos round the opaque parts of the image where the background is light.
+In the OPTIMIZED mode the halos will be light halos where the background
+is dark.  Take your pick - the halos are unavoidable unless you can get
+your hardware/software fixed!  (The OPTIMIZED approach is slightly
+faster.)
+
+When the default gamma of PNG files doesn't match the output gamma.
+If you have PNG files with no gamma information png_set_alpha_mode allows
+you to provide a default gamma, but it also sets the ouput gamma to the
+matching value.  If you know your PNG files have a gamma that doesn't
+match the output you can take advantage of the fact that
+png_set_alpha_mode always sets the output gamma but only sets the PNG
+default if it is not already set:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+The first call sets both the default and the output gamma values, the
+second call overrides the output gamma without changing the default.  This
+is easier than achieving the same effect with png_set_gamma.  You must use
+PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+fire if more than one call to png_set_alpha_mode and png_set_background is
+made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+are ignored.
+
 If you don't need, or can't handle, the alpha channel you can call
 png_set_background() to remove it by compositing against a fixed color.  Don't
 call png_set_strip_alpha() to do this - it will leave spurious pixel values in
@@ -1720,7 +1888,7 @@ png_set_rgb_to_gray()).

    png_get_sRGB(png_ptr, info_ptr, &srgb_intent);

-    file_srgb_intent - the rendering intent (PNG_INFO_sRGB)
+    srgb_intent -    the rendering intent (PNG_INFO_sRGB)
                     The presence of the sRGB chunk
                     means that the pixel data is in the
                     sRGB color space.  This chunk also
@@ -2670,10 +2838,15 @@ how pngvalid.c does it.
 .SS Finishing a sequential read

 After you are finished reading the image through the
-low-level interface, you can finish reading the file.  If you are
-interested in comments or time, which may be stored either before or
-after the image data, you should pass the separate png_info struct if
-you want to keep the comments from before and after the image
+low-level interface, you can finish reading the file.
+
+If you want to use a different crc action for handling CRC errors in
+chunks after the image data, you can call png_set_crc_action()
+again at this point.
+
+If you are interested in comments or time, which may be stored either
+before or after the image data, you should pass the separate png_info
+struct if you want to keep the comments from before and after the image
 separate.

    png_infop end_info = png_create_info_struct(png_ptr);
@@ -2689,6 +2862,9 @@ separate.

 If you are not interested, you should still call png_read_end()
 but you can pass NULL, avoiding the need to create an end_info structure.
+If you do this, libpng will not process any chunks after IDAT other than
+skipping over them and perhaps (depending on whether you have called
+png_set_crc_action) checking their CRCs while looking for the IEND chunk.

   png_read_end(png_ptr, (png_infop)NULL);

@@ -2964,7 +3140,7 @@ png_infop info_ptr;
        png_progressive_combine_row(png_ptr, old_row,
          new_row);

-    /* where old_row is what was displayed for
+    /* where old_row is what was displayed
       previously for the row.  Note that the first
       pass (pass == 0, really) will completely cover
       the old row, so the rows do not have to be
@@ -3589,7 +3765,7 @@ tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
 although this isn't a requirement.  Unlike the tIME chunk, the
 "Creation Time" tEXt chunk is not expected to be automatically changed
 by the software.  To facilitate the use of RFC 1123 dates, a function
-png_convert_to_rfc1123_buffer(png_ptr, buffer, png_timep) is provided to
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
 convert from PNG time to an RFC 1123 format string.  The caller must provide
 a writeable buffer of at least 29 bytes.

@@ -4121,8 +4297,9 @@ and matches the 8-bit format expected by typical display devices.
 The color/gray channels are not scaled (pre-multiplied) by the alpha
 channel and are suitable for passing to color management software.

-  b) As a value in the range 0..65535, contained in a 2-byte integer.  All
-channels can be converted to the original value by dividing by 65535; all
+  b) As a value in the range 0..65535, contained in a 2-byte integer, in
+the native byte order of the platform on which the application is running.
+All channels can be converted to the original value by dividing by 65535; all
 channels are linear.  Color channels use the RGB encoding (RGB end-points) of
 the sRGB specification.  This encoding is identified by the
 PNG_FORMAT_FLAG_LINEAR flag below.
@@ -4189,7 +4366,9 @@ First the single byte formats:
 Then the linear 2-byte formats.  When naming these "Y" is used to
 indicate a luminance (gray) channel.  The component order within the pixel
 is always the same - there is no provision for swapping the order of the
-components in the linear format.
+components in the linear format.  The components are 16-bit integers in
+the native byte order for your platform, and there is no provision for
+swapping the bytes to a different endian condition.

   PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
   PNG_FORMAT_LINEAR_Y_ALPHA
@@ -4254,7 +4433,7 @@ First the information about the samples.
    *
    * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
    *
-    * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+    * Alternatively, use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
    * information from one of the png_image_begin_read_ APIs and dynamically
    * allocate the required memory.
    */
@@ -4283,9 +4462,16 @@ Information about the whole row, or whole image
   row.  For a color-mapped image this is the minimum number of bytes in a
   row.

+   If you need the stride measured in bytes, row_stride_bytes is
+   PNG_IMAGE_ROW_STRIDE(image) * PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)
+   plus any padding bytes that your application might need, for example
+   to start the next row on a 4-byte boundary.
+
  PNG_IMAGE_BUFFER_SIZE(image, row_stride)
    Returns the size, in bytes, of an image buffer given a png_image and a row
-    stride - the number of components to leave space for in each row.
+    stride - the number of components to leave space for in each row.  This
+    macro takes care of multiplying row_stride by PNG_IMAGE_PIXEL_COMONENT_SIZE
+    when the image has 2-byte components.

  PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01
    This indicates the the RGB values of the in-memory bitmap do not
@@ -4414,14 +4600,11 @@ clears the newly allocated memory to zero; note that png_calloc(png_ptr, size)
 is not the same as the calloc(number, size) function provided by stdlib.h.
 There is limited support for certain systems with segmented memory
 architectures and the types of pointers declared by png.h match this; you
-will have to use appropriate pointers in your application.  Since it is
-unlikely that the method of handling memory allocation on a platform
-will change between applications, these functions must be modified in
-the library at compile time.  If you prefer to use a different method
-of allocating and freeing data, you can use png_create_read_struct_2() or
-png_create_write_struct_2() to register your own functions as described
-above.  These functions also provide a void pointer that can be retrieved
-via
+will have to use appropriate pointers in your application.  If you prefer
+to use a different method of allocating and freeing data, you can use
+png_create_read_struct_2() or png_create_write_struct_2() to register your
+own functions as described above.  These functions also provide a void
+pointer that can be retrieved via

    mem_ptr=png_get_mem_ptr(png_ptr);

@@ -4564,29 +4747,6 @@ the simpler ones to get an idea of how they work.  Try to find a similar
 transformation to the one you want to add and copy off of it.  More details
 can be found in the comments inside the code itself.

-.SS Configuring for 16-bit platforms
-
-You will want to look into zconf.h to tell zlib (and thus libpng) that
-it cannot allocate more then 64K at a time.  Even if you can, the memory
-won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.
-
-.SS Configuring for DOS
-
-For DOS users who only have access to the lower 640K, you will
-have to limit zlib's memory usage via a png_set_compression_mem_level()
-call.  See zlib.h or zconf.h in the zlib library for more information.
-
-.SS Configuring for Medium Model
-
-Libpng's support for medium model has been tested on most of the popular
-compilers.  Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
-defined, and FAR gets defined to far in pngconf.h, and you should be
-all set.  Everything in the library (except for zlib's structure) is
-expecting far data.  You must use the typedefs with the p or pp on
-the end for pointers (or at least look at them and be careful).  Make
-note that the rows of data are defined as png_bytepp, which is
-an "unsigned char far * far *".
-
 .SS Configuring for gui/windowing platforms:

 You will need to write new error and warning functions that use the GUI
@@ -4596,19 +4756,6 @@ in order to have them available during the structure initialization.
 They can be changed later via png_set_error_fn().  On some compilers,
 you may also have to change the memory allocators (png_malloc, etc.).

-.SS Configuring for compiler xxx:
-
-All includes for libpng are in pngconf.h.  If you need to add, change
-or delete an include, this is the place to do it.
-The includes that are not needed outside libpng are placed in pngpriv.h,
-which is only used by the routines inside libpng itself.
-The files in libpng proper only include pngpriv.h and png.h, which
-%14%in turn includes pngconf.h.
-in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
-As of libpng-1.5.0, pngpriv.h also includes three other private header
-files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
-that previously appeared in the public headers.
-
 .SS Configuring zlib:

 There are special functions to configure the compression.  Perhaps the
@@ -4650,6 +4797,8 @@ zlib.h for more information on what these mean.

    png_set_compression_method(png_ptr, method);

+This controls the size of the IDAT chunks (default 8192):
+
    png_set_compression_buffer_size(png_ptr, size);

 As of libpng version 1.5.4, additional APIs became
@@ -4748,46 +4897,6 @@ Note that the numbers above were invented purely for this example and
 are given only to help explain the function usage.  Little testing has
 been done to find optimum values for either the costs or the weights.

-.SS Removing unwanted object code
-
-There are a bunch of #define's in pngconf.h that control what parts of
-libpng are compiled.  All the defines end in _SUPPORTED.  If you are
-never going to use a capability, you can change the #define to #undef
-before recompiling libpng and save yourself code and data space, or
-you can turn off individual capabilities with defines that begin with
-PNG_NO_.
-
-In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
-
-You can also turn all of the transforms and ancillary chunk capabilities
-off en masse with compiler directives that define
-PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
-or all four,
-along with directives to turn on any of the capabilities that you do
-want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the extra
-transformations but still leave the library fully capable of reading
-and writing PNG files with all known public chunks. Use of the
-PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
-that is incapable of reading or writing ancillary chunks.  If you are
-not using the progressive reading capability, you can turn that off
-with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
-capability, which you'll still have).
-
-All the reading and writing specific code are in separate files, so the
-linker should only grab the files it needs.  However, if you want to
-make sure, or if you are building a stand alone library, all the
-reading files start with "pngr" and all the writing files start with "pngw".
-The files that don't match either (like png.c, pngtrans.c, etc.)
-are used for both reading and writing, and always need to be included.
-The progressive reader is in pngpread.c
-
-If you are creating or distributing a dynamically linked library (a .so
-or DLL file), you should not remove or disable any parts of the library,
-as this will cause applications linked with different versions of the
-library to fail if they call functions not available in your library.
-The size of the library itself should not be an issue, because only
-those sections that are actually used will be loaded into memory.
-
 .SS Requesting debug printout

 The macro definition PNG_DEBUG can be used to request debugging
@@ -4825,17 +4934,6 @@ When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
 having level = 0 will be printed.  There aren't any such statements in
 this version of libpng, but if you insert some they will be printed.

-.SS Prepending a prefix to exported symbols
-
-Starting with libpng-1.6.0, you can configure libpng (when using the
-"configure" script) to prefix all exported symbols by means of the
-configuration option "\-\-with\-libpng\-prefix=FOO_", where FOO_ can be any
-string beginning with a letter and containing only uppercase
-and lowercase letters, digits, and the underscore (i.e., a C language
-identifier).  This creates a set of macros in pnglibconf.h, so this is
-transparent to applications; their function calls get transformed by
-the macros to use the modified names.
-
 .SH VII.  MNG support

 The MNG specification (available at http://www.libpng.org/pub/mng) allows
@@ -4898,6 +4996,9 @@ png_set_error_fn(), which is essentially the same function, but with a new
 name to force compilation errors with applications that try to use the old
 method.

+Support for the sCAL, iCCP, iTXt, and sPLT chunks was added at libpng-1.0.6;
+however, iTXt support was not enabled by default.
+
 Starting with version 1.0.7, you can find out which version of the library
 you are using at run-time:

@@ -5126,6 +5227,7 @@ We removed the trailing '.' from the warning and error messages.

 From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
 function) incorrectly returned a value of type png_uint_32.
+The incorrect macro was removed from libpng-1.4.5.

 Checking for invalid palette index on write was added at libpng
 1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
@@ -5158,8 +5260,6 @@ does not account for any palette index used by ancillary chunks such as the
 bKGD chunk; you must check those separately to determine the maximum
 palette index actually used.

-A. Changes that affect users of libpng
-
 There are no substantial API changes between the non-deprecated parts of
 the 1.4.5 API and the 1.5.0 API; however, the ability to directly access
 members of the main libpng control structures, png_struct and png_info,
@@ -5230,7 +5330,10 @@ and the accuracy of PNG fixed point values is insufficient for
 representation of these values. Consequently a "string" API
 (png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
 arbitrary sCAL chunks in the absence of either the floating point API or
-internal floating point calculations.
+internal floating point calculations.  Starting with libpng-1.5.0, both
+of these functions are present when PNG_sCAL_SUPPORTED is defined.  Prior
+to libpng-1.5.0, their presence also depended upon PNG_FIXED_POINT_SUPPORTED
+being defined and PNG_FLOATING_POINT_SUPPORTED not being defined.

 Applications no longer need to include the optional distribution header
 file pngusr.h or define the corresponding macros during application
@@ -5250,11 +5353,6 @@ reset by pngusr.h or by explicit settings on the compiler command line.
 These settings may produce compiler warnings or errors in 1.5.0 because
 of macro redefinition.

-From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
-function) incorrectly returned a value of type png_uint_32.  libpng 1.5.0
-is consistent with the implementation in 1.4.5 and 1.2.x (where the macro
-did not exist.)
-
 Applications can now choose whether to use these macros or to call the
 corresponding function by defining PNG_USE_READ_MACROS or
 PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
@@ -5272,7 +5370,10 @@ option was off by default, and slightly inaccurate scaling occurred.
 This option can no longer be turned off, and the choice of accurate
 or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
 API for accurate scaling or the old png_set_strip_16_to_8() API for simple
-chopping.
+chopping.  In libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+macro became PNG_READ_SCALE_16_TO_8_SUPPORTED, and the PNG_READ_16_TO_8
+macro became PNG_READ_STRIP_16_TO_8_SUPPORTED, to enable the two
+png_set_*_16_to_8() functions separately.

 Prior to libpng-1.5.4, the png_set_user_limits() function could only be
 used to reduce the width and height limits from the value of
@@ -5297,26 +5398,6 @@ limits are now
 The png_set_option() function (and the "options" member of the png struct) was
 added to libpng-1.5.15.

-B. Changes to the build and configuration of libpng
-
-Details of internal changes to the library code can be found in the CHANGES
-file and in the GIT repository logs.  These will be of no concern to the vast
-majority of library users or builders; however, the few who configure libpng
-to a non-default feature set may need to change how this is done.
-
-There should be no need for library builders to alter build scripts if
-these use the distributed build support - configure or the makefiles -
-however, users of the makefiles may care to update their build scripts
-to build pnglibconf.h where the corresponding makefile does not do so.
-
-Building libpng with a non-default configuration has changed completely.
-The old method using pngusr.h should still work correctly even though the
-way pngusr.h is used in the build has been changed; however, library
-builders will probably want to examine the changes to take advantage of
-new capabilities and to simplify their build system.
-
-B.1 Specific changes to library configuration capabilities
-
 The library now supports a complete fixed point implementation and can
 thus be used on systems that have no floating point support or very
 limited or slow support.  Previously gamma correction, an essential part
@@ -5327,27 +5408,7 @@ independent of the choice of fixed versus floating point APIs and all the
 missing fixed point APIs have been implemented.

 The exact mechanism used to control attributes of API functions has
-changed.  A single set of operating system independent macro definitions
-is used and operating system specific directives are defined in
-pnglibconf.h
-
-As part of this the mechanism used to choose procedure call standards on
-those systems that allow a choice has been changed.  At present this only
-affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
-running on Intel processors.  As before, PNGAPI is defined where required
-to control the exported API functions; however, two new macros, PNGCBAPI
-and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
-(PNGCAPI) for functions that must match a C library prototype (currently
-only png_longjmp_ptr, which must match the C longjmp function.)  The new
-approach is documented in pngconf.h
-
-Despite these changes, libpng 1.5.0 only supports the native C function
-calling standard on those platforms tested so far (__cdecl on Microsoft
-Windows).  This is because the support requirements for alternative
-calling conventions seem to no longer exist.  Developers who find it
-necessary to set PNG_API_RULE to 1 should advise the mailing list
-(png-mng-implement) of this and library builders who use Openwatcom and
-therefore set PNG_API_RULE to 2 should also contact the mailing list.
+changed, as described in the INSTALL file.

 A new test program, pngvalid, is provided in addition to pngtest.
 pngvalid validates the arithmetic accuracy of the gamma correction
@@ -5423,46 +5484,6 @@ even though the default is to use the macros - this allows applications
 to choose at app buildtime whether or not to use macros (previously
 impossible because the functions weren't in the default build.)

-B.2 Changes to the configuration mechanism
-
-Prior to libpng-1.5.0 library builders who needed to configure libpng
-had either to modify the exported pngconf.h header file to add system
-specific configuration or had to write feature selection macros into
-pngusr.h and cause this to be included into pngconf.h by defining
-PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
-application built without PNG_USER_CONFIG defined would see the
-unmodified, default, libpng API and thus would probably fail to link.
-
-These mechanisms still work in the configure build and in any makefile
-build that builds pnglibconf.h, although the feature selection macros
-have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
-processed only once, when the exported header file pnglibconf.h is built.
-pngconf.h no longer includes pngusr.h, therefore pngusr.h is ignored after the
-build of pnglibconf.h and it is never included in an application build.
-
-The rarely used alternative of adding a list of feature macros to the
-CFLAGS setting in the build also still works; however, the macros will be
-copied to pnglibconf.h and this may produce macro redefinition warnings
-when the individual C files are compiled.
-
-All configuration now only works if pnglibconf.h is built from
-scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
-(the original author of awk) maintains C source code of that awk and this
-and all known later implementations (often called by subtly different
-names - nawk and gawk for example) are adequate to build pnglibconf.h.
-The Sun Microsystems (now Oracle) program 'awk' is an earlier version
-and does not work; this may also apply to other systems that have a
-functioning awk called 'nawk'.
-
-Configuration options are now documented in scripts/pnglibconf.dfa.  This
-file also includes dependency information that ensures a configuration is
-consistent; that is, if a feature is switched off dependent features are
-also removed.  As a recommended alternative to using feature macros in
-pngusr.h a system builder may also define equivalent options in pngusr.dfa
-(or, indeed, any file) and add that to the configuration by setting
-DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
-how to do this, and a case where pngusr.h is still required.
-
 .SH XII.  Changes to Libpng from version 1.5.x to 1.6.x

 A "simplified API" has been added (see documentation in png.h and a simple
@@ -5498,7 +5519,6 @@ The following API are now DEPRECATED:
   png_info_init_3()
   png_convert_to_rfc1123() which has been replaced
     with png_convert_to_rfc1123_buffer()
-   png_data_freer()
   png_malloc_default()
   png_free_default()
   png_reset_zstream()
@@ -5522,11 +5542,26 @@ Error detection in some chunks has improved; in particular the iCCP chunk
 reader now does pretty complete validation of the basic format.  Some bad
 profiles that were previously accepted are now accepted with a warning or
 rejected, depending upon the png_set_benign_errors() setting, in particular the
-very old broken Microsoft/HP 3144-byte sRGB profile.  The PNG spec requirement
-that only grayscale profiles may appear in images with color type 0 or 4 and
-that even if the image only contains gray pixels, only RGB profiles may appear
-in images with color type 2, 3, or 6, is now enforced.  The sRGB chunk
-is allowed to appear in images with any color type.
+very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
+libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
+means of
+
+    #if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && \
+        defined(PNG_SET_OPTION_SUPPORTED)
+       png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE,
+           PNG_OPTION_ON);
+    #endif
+
+It's not a good idea to do this if you are using the "simplified API",
+which needs to be able to recognize an sRGB profile conveyed via the iCCP
+chunk.
+
+The PNG spec requirement that only grayscale profiles may appear in images
+with color type 0 or 4 and that even if the image only contains gray pixels,
+only RGB profiles may appear in images with color type 2, 3, or 6, is now
+enforced.  The sRGB chunk is allowed to appear in images with any color type
+and is interpreted by libpng to convey a one-tracer-curve gray profile or a
+three-tracer-curve RGB profile as appropriate.

 Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
 an empty language field or an empty translated keyword.  Both of these
@@ -5560,16 +5595,16 @@ Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT
 stream to set the size of the sliding window for reading instead of using the
 default 32-kbyte sliding window size.  It was discovered that there are
 hundreds of PNG files in the wild that have incorrect CMF bytes that caused
-libpng to issue a "too far back" error and reject the file.  Libpng-1.6.3 and
-later calculate their own safe CMF from the image dimensions, provide a way
-to revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a
-32-kbyte sliding window), by using
+zlib to issue the "invalid distance too far back" error and reject the file.
+Libpng-1.6.3 and later calculate their own safe CMF from the image dimensions,
+provide a way to revert to the libpng-1.5.x behavior (ignoring the CMF bytes
+and using a 32-kbyte sliding window), by using

    png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW,
        PNG_OPTION_ON);

-and provide a tool (contrib/tools/pngfix) for optimizing the CMF bytes
-correctly.
+and provide a tool (contrib/tools/pngfix) for rewriting a PNG file while
+optimizing the CMF bytes in its IDAT chunk correctly.

 Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
 length, which resulted in PNG files that cannot be read beyond the bad iTXt
@@ -5611,7 +5646,8 @@ mailing list, or directly to glennrp.

 .SH XV. Coding style

-Our coding style is similar to the "Allman" style, with curly
+Our coding style is similar to the "Allman" style
+(See http://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
 braces on separate lines:

    if (condition)
@@ -5674,6 +5710,9 @@ exported functions are marked with PNGAPI:
    body;
 }

+The return type and decorations are placed on a separate line
+ahead of the function name, as illustrated above.
+
 The prototypes for all exported functions appear in png.h,
 above the comment that says

@@ -5688,12 +5727,15 @@ We mark all non-exported functions with "/* PRIVATE */"":
 }

 The prototypes for non-exported functions (except for those in
-pngtest) appear in
-pngpriv.h
-above the comment that says
+pngtest) appear in pngpriv.h above the comment that says

  /* Maintainer: Put new private prototypes here ^ */

+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
 We put a space after the "sizeof" operator and we omit the
 optional parentheses around its argument when the argument
 is an expression, not a type name, and we always enclose the
@@ -5705,10 +5747,8 @@ sizeof operator, with its argument, in parentheses:
 Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
 though it were a function.

-To avoid polluting the global namespace, the names of all exported
-functions and variables begin with "png_", and all publicly visible C
-preprocessor macros begin with "PNG".  We request that applications that
-use libpng *not* begin any of their own symbols with either of these strings.
+Control keywords if, for, while, and switch are always followed by a space
+to distinguish them from function calls, which have no trailing space. 

 We put a space after each comma and after each semicolon
 in "for" statements, and we put spaces before and after each
@@ -5730,6 +5770,9 @@ with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100).
 We prefer to use underscores in variable names rather than camelCase, except
 for a few type names that we inherit from zlib.h.

+We prefer "if (something != 0)" and "if (something == 0)"
+over "if (something)" and if "(!something)", respectively.
+
 We do not use the TAB character for indentation in the C sources.

 Lines do not exceed 80 characters.
@@ -5738,13 +5781,13 @@ Other rules can be inferred by inspecting the libpng source.

 .SH XVI. Y2K Compliance in libpng

-January 1, 2014
+November 20, 2014

 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.

 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.6.9beta02 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.15 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.

 Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -5760,8 +5803,9 @@ in libpng-1.6.x and will be removed from libpng-1.7.0.

 There are seven time-related functions:

-    png_convert_to_rfc_1123() in png.c
-      (formerly png_convert_to_rfc_1152() in error)
+    png_convert_to_rfc_1123_buffer() in png.c
+      (formerly png_convert_to_rfc_1152() in error, and
+      also formerly png_convert_to_rfc_1123())
    png_convert_from_struct_tm() in pngwrite.c, called
      in pngwrite.c
    png_convert_from_time_t() in pngwrite.c
@@ -5972,7 +6016,26 @@ the first widely used release:
 1.6.8beta01-02      16    10608  16.so.16.8[.0]
 1.6.8rc01-02        16    10608  16.so.16.8[.0]
 1.6.8               16    10608  16.so.16.8[.0]
- 1.6.8beta01-02      16    10609  16.so.16.9[.0]
+ 1.6.9beta01-04      16    10609  16.so.16.9[.0]
+ 1.6.9rc01-02        16    10609  16.so.16.9[.0]
+ 1.6.9               16    10609  16.so.16.9[.0]
+ 1.6.10beta01-03     16    10610  16.so.16.10[.0]
+ 1.6.10rc01-03       16    10610  16.so.16.10[.0]
+ 1.6.10              16    10610  16.so.16.10[.0]
+ 1.6.11beta01-06     16    10611  16.so.16.11[.0]
+ 1.6.11rc01-02       16    10611  16.so.16.11[.0]
+ 1.6.11              16    10611  16.so.16.11[.0]
+ 1.6.12rc01          16    10612  16.so.16.12[.0]
+ 1.6.12              16    10612  16.so.16.12[.0]
+ 1.6.13beta01-04     16    10613  16.so.16.13[.0]
+ 1.6.13rc01-02       16    10613  16.so.16.13[.0]
+ 1.6.13              16    10613  16.so.16.13[.0]
+ 1.6.14beta01-07     16    10614  16.so.16.14[.0]
+ 1.6.14rc01-02       16    10614  16.so.16.14[.0]
+ 1.6.14              16    10614  16.so.16.14[.0]
+ 1.6.15beta01-08     16    10615  16.so.16.15[.0]
+ 1.6.15rc01-03       16    10615  16.so.16.15[.0]
+ 1.6.15              16    10615  16.so.16.15[.0]

 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6029,7 +6092,7 @@ possible without all of you.

 Thanks to Frank J. T. Wojcik for helping with the documentation.

-Libpng version 1.6.9beta02 - January 1, 2014:
+Libpng version 1.6.15 - November 20, 2014:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).

@@ -6052,8 +6115,8 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.6.9beta02, January 1, 2014, are
-Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
+libpng versions 1.2.6, August 15, 2004, through 1.6.15, November 20, 2014, are
+Copyright (c) 2004,2006-2014 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors

@@ -6151,7 +6214,7 @@ certification mark of the Open Source Initiative.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-January 1, 2014
+November 20, 2014

 .\" end of man page

--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "January 1, 2014"
+.TH LIBPNGPF 3 "November 20, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.9beta02
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.15
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "January 1, 2014"
+.TH PNG 5 "November 20, 2014"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
--- a/png.c
+++ b/png.c
--- a/png.h
+++ b/png.h
@@ -1,8 +1,8 @@

 /* png.h - header file for PNG reference library
 *
- * libpng version 1.6.9beta02 - January 1, 2014
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * libpng version 1.6.15, November 20, 2014
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -11,7 +11,7 @@
 * Authors and maintainers:
 *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
 *   libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.6.9beta02 - January 1, 2014: Glenn
+ *   libpng versions 0.97, January 1998, through 1.6.15, November 20, 2014: Glenn
 *   See also "Contributing Authors", below.
 *
 * Note about libpng version numbers:
@@ -189,7 +189,26 @@
 *    1.6.8beta01-02          16    10608  16.so.16.8[.0]
 *    1.6.8rc01-02            16    10608  16.so.16.8[.0]
 *    1.6.8                   16    10608  16.so.16.8[.0]
- *    1.6.9beta01-02          16    10609  16.so.16.9[.0]
+ *    1.6.9beta01-04          16    10609  16.so.16.9[.0]
+ *    1.6.9rc01-02            16    10609  16.so.16.9[.0]
+ *    1.6.9                   16    10609  16.so.16.9[.0]
+ *    1.6.10beta01-03         16    10610  16.so.16.10[.0]
+ *    1.6.10rc01-03           16    10610  16.so.16.10[.0]
+ *    1.6.10                  16    10610  16.so.16.10[.0]
+ *    1.6.11beta01-06         16    10611  16.so.16.11[.0]
+ *    1.6.11rc01-02           16    10611  16.so.16.11[.0]
+ *    1.6.11                  16    10611  16.so.16.11[.0]
+ *    1.6.12rc01-03           16    10612  16.so.16.12[.0]
+ *    1.6.12                  16    10612  16.so.16.12[.0]
+ *    1.6.13beta01-04         16    10613  16.so.16.13[.0]
+ *    1.6.13rc01-02           16    10613  16.so.16.13[.0]
+ *    1.6.13                  16    10613  16.so.16.13[.0]
+ *    1.6.14beta01-07         16    10614  16.so.16.14[.0]
+ *    1.6.14rc01-02           16    10614  16.so.16.14[.0]
+ *    1.6.14                  16    10614  16.so.16.14[.0]
+ *    1.6.15beta01-08         16    10615  16.so.16.15[.0]
+ *    1.6.15rc01-03           16    10615  16.so.16.15[.0]
+ *    1.6.15                  16    10615  16.so.16.15[.0]
 *
 *   Henceforth the source version will match the shared-library major
 *   and minor numbers; the shared-library major version number will be
@@ -221,8 +240,8 @@
 *
 * This code is released under the libpng license.
 *
- * libpng versions 1.2.6, August 15, 2004, through 1.6.9beta02, January 1, 2014, are
- * Copyright (c) 2004, 2006-2013 Glenn Randers-Pehrson, and are
+ * libpng versions 1.2.6, August 15, 2004, through 1.6.15, November 20, 2014, are
+ * Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
 * distributed according to the same disclaimer and license as libpng-1.2.5
 * with the following individual added to the list of Contributing Authors:
 *
@@ -333,13 +352,13 @@
 * Y2K compliance in libpng:
 * =========================
 *
- *    January 1, 2014
+ *    November 20, 2014
 *
 *    Since the PNG Development group is an ad-hoc body, we can't make
 *    an official declaration.
 *
 *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.6.9beta02 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.15 are Y2K compliant.  It is my belief that
 *    earlier versions were also Y2K compliant.
 *
 *    Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -392,16 +411,18 @@
 /* This is not the place to learn how to use libpng. The file libpng-manual.txt
 * describes how to use libpng, and the file example.c summarizes it
 * with some code on which to build.  This file is useful for looking
- * at the actual function definitions and structure components.
+ * at the actual function definitions and structure components.  If that
+ * file has been stripped from your copy of libpng, you can find it at
+ * <http://www.libpng.org/pub/png/libpng-manual.txt>
 *
 * If you just need to read a PNG file and don't want to read the documentation
 * skip to the end of this file and read the section entitled 'simplified API'.
 */

 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.9beta02"
+#define PNG_LIBPNG_VER_STRING "1.6.15"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.6.9beta02 - January 1, 2014\n"
+     " libpng version 1.6.15 - November 20, 2014\n"

 #define PNG_LIBPNG_VER_SONUM   16
 #define PNG_LIBPNG_VER_DLLNUM  16
@@ -409,13 +430,13 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 9
+#define PNG_LIBPNG_VER_RELEASE 15

 /* This should match the numeric part of the final component of
 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
 */

-#define PNG_LIBPNG_VER_BUILD  02
+#define PNG_LIBPNG_VER_BUILD  0

 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -432,7 +453,7 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                       PNG_LIBPNG_BUILD_PRIVATE */

-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE

 /* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
 * We must not include leading zeros.
@@ -440,7 +461,7 @@
 * version 1.0.0 was mis-numbered 100 instead of 10000).  From
 * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
 */
-#define PNG_LIBPNG_VER 10609 /* 1.6.9 */
+#define PNG_LIBPNG_VER 10615 /* 1.6.15 */

 /* Library configuration: these options cannot be changed after
 * the library has been built.
@@ -545,7 +566,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
 * do not agree upon the version number.
 */
-typedef char* png_libpng_version_1_6_9beta02;
+typedef char* png_libpng_version_1_6_15;

 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
 *
@@ -1158,7 +1179,7 @@ PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,

 /* Convert from time_t to png_time.  Uses gmtime() */
 PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
-#endif /* PNG_CONVERT_tIME_SUPPORTED */
+#endif /* CONVERT_tIME */

 #ifdef PNG_READ_EXPAND_SUPPORTED
 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
@@ -1207,9 +1228,9 @@ PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
 #endif

 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-/* How the alpha channel is interpreted - this affects how the color channels of
- * a PNG file are returned when an alpha channel, or tRNS chunk in a palette
- * file, is present.
+/* How the alpha channel is interpreted - this affects how the color channels
+ * of a PNG file are returned to the calling application when an alpha channel,
+ * or a tRNS chunk in a palette file, is present.
 *
 * This has no effect on the way pixels are written into a PNG output
 * datastream. The color samples in a PNG datastream are never premultiplied
@@ -1217,33 +1238,19 @@ PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
 *
 * The default is to return data according to the PNG specification: the alpha
 * channel is a linear measure of the contribution of the pixel to the
- * corresponding composited pixel.  The gamma encoded color channels must be
- * scaled according to the contribution and to do this it is necessary to undo
+ * corresponding composited pixel, and the color channels are unassociated
+ * (not premultiplied).  The gamma encoded color channels must be scaled
+ * according to the contribution and to do this it is necessary to undo
 * the encoding, scale the color values, perform the composition and reencode
 * the values.  This is the 'PNG' mode.
 *
 * The alternative is to 'associate' the alpha with the color information by
- * storing color channel values that have been scaled by the alpha.  The
- * advantage is that the color channels can be resampled (the image can be
- * scaled) in this form.  The disadvantage is that normal practice is to store
- * linear, not (gamma) encoded, values and this requires 16-bit channels for
- * still images rather than the 8-bit channels that are just about sufficient if
- * gamma encoding is used.  In addition all non-transparent pixel values,
- * including completely opaque ones, must be gamma encoded to produce the final
- * image.  This is the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' mode (the
- * latter being the two common names for associated alpha color channels.)
+ * storing color channel values that have been scaled by the alpha.
+ * image.  These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+ * (the latter being the two common names for associated alpha color channels).
 *
- * Since it is not necessary to perform arithmetic on opaque color values so
- * long as they are not to be resampled and are in the final color space it is
- * possible to optimize the handling of alpha by storing the opaque pixels in
- * the PNG format (adjusted for the output color space) while storing partially
- * opaque pixels in the standard, linear, format.  The accuracy required for
- * standard alpha composition is relatively low, because the pixels are
- * isolated, therefore typically the accuracy loss in storing 8-bit linear
- * values is acceptable.  (This is not true if the alpha channel is used to
- * simulate transparency over large areas - use 16 bits or the PNG mode in
- * this case!)  This is the 'OPTIMIZED' mode.  For this mode a pixel is
- * treated as opaque only if the alpha value is equal to the maximum value.
+ * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
+ * value is equal to the maximum value.
 *
 * The final choice is to gamma encode the alpha channel as well.  This is
 * broken because, in practice, no implementation that uses this choice
@@ -1270,68 +1277,7 @@ PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,

 #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
 /* The output_gamma value is a screen gamma in libpng terminology: it expresses
- * how to decode the output values, not how they are encoded.  The values used
- * correspond to the normal numbers used to describe the overall gamma of a
- * computer display system; for example 2.2 for an sRGB conformant system.  The
- * values are scaled by 100000 in the _fixed version of the API (so 220000 for
- * sRGB.)
- *
- * The inverse of the value is always used to provide a default for the PNG file
- * encoding if it has no gAMA chunk and if png_set_gamma() has not been called
- * to override the PNG gamma information.
- *
- * When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
- * opaque pixels however pixels with lower alpha values are not encoded,
- * regardless of the output gamma setting.
- *
- * When the standard Porter Duff handling is requested with mode 1 the output
- * encoding is set to be linear and the output_gamma value is only relevant
- * as a default for input data that has no gamma information.  The linear output
- * encoding will be overridden if png_set_gamma() is called - the results may be
- * highly unexpected!
- *
- * The following numbers are derived from the sRGB standard and the research
- * behind it.  sRGB is defined to be approximated by a PNG gAMA chunk value of
- * 0.45455 (1/2.2) for PNG.  The value implicitly includes any viewing
- * correction required to take account of any differences in the color
- * environment of the original scene and the intended display environment; the
- * value expresses how to *decode* the image for display, not how the original
- * data was *encoded*.
- *
- * sRGB provides a peg for the PNG standard by defining a viewing environment.
- * sRGB itself, and earlier TV standards, actually use a more complex transform
- * (a linear portion then a gamma 2.4 power law) than PNG can express.  (PNG is
- * limited to simple power laws.)  By saying that an image for direct display on
- * an sRGB conformant system should be stored with a gAMA chunk value of 45455
- * (11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
- * makes it possible to derive values for other display systems and
- * environments.
- *
- * The Mac value is deduced from the sRGB based on an assumption that the actual
- * extra viewing correction used in early Mac display systems was implemented as
- * a power 1.45 lookup table.
- *
- * Any system where a programmable lookup table is used or where the behavior of
- * the final display device characteristics can be changed requires system
- * specific code to obtain the current characteristic.  However this can be
- * difficult and most PNG gamma correction only requires an approximate value.
- *
- * By default, if png_set_alpha_mode() is not called, libpng assumes that all
- * values are unencoded, linear, values and that the output device also has a
- * linear characteristic.  This is only very rarely correct - it is invariably
- * better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
- * default if you don't know what the right answer is!
- *
- * The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
- * 10.6) which used a correction table to implement a somewhat lower gamma on an
- * otherwise sRGB system.
- *
- * Both these values are reserved (not simple gamma values) in order to allow
- * more precise correction internally in the future.
- *
- * NOTE: the following values can be passed to either the fixed or floating
- * point APIs, but the floating point API will also accept floating point
- * values.
+ * how to decode the output values, not how they are encoded.
 */
 #define PNG_DEFAULT_sRGB -1       /* sRGB gamma and color space */
 #define PNG_GAMMA_MAC_18 -2       /* Old Mac '1.8' gamma and color space */
@@ -1439,7 +1385,7 @@ PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
 PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
    png_uint_32 filler, int flags));
-#endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */
+#endif /* READ_FILLER || WRITE_FILLER */

 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
 /* Swap bytes in 16-bit depth files. */
@@ -1703,7 +1649,7 @@ PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
    (png_structrp png_ptr, int heuristic_method, int num_weights,
    png_const_fixed_point_p filter_weights,
    png_const_fixed_point_p filter_costs))
-#endif /*  PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
+#endif /* WRITE_WEIGHTED_FILTER */

 /* Heuristic used for row filter selection.  These defines should NOT be
 * changed.
@@ -1759,7 +1705,7 @@ PNG_EXPORT(225, void, png_set_text_compression_window_bits,

 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
    int method));
-#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */

 /* These next functions are called for input/output, memory, and error
 * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
@@ -1919,7 +1865,6 @@ PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));
 */
 PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));

-#ifdef PNG_READ_INTERLACING_SUPPORTED
 /* Function that combines rows.  'new_row' is a flag that should come from
 * the callback and be non-NULL if anything needs to be done; the library
 * stores its own version of the new data internally and ignores the passed
@@ -1927,8 +1872,7 @@ PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
 */
 PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
    png_bytep old_row, png_const_bytep new_row));
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+#endif /* PROGRESSIVE_READ */

 PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
    png_alloc_size_t size), PNG_ALLOCATED);
@@ -1954,8 +1898,8 @@ PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
 * It is unlikely that this function works correctly as of 1.6.0 and using it
 * may result either in memory leaks or double free of allocated data.
 */
-PNG_EXPORTA(99, void, png_data_freer, (png_const_structrp png_ptr,
-    png_inforp info_ptr, int freer, png_uint_32 mask), PNG_DEPRECATED);
+PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int freer, png_uint_32 mask));

 /* Assignments for png_data_freer */
 #define PNG_DESTROY_WILL_FREE_DATA 1
@@ -1997,6 +1941,8 @@ PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
 #else
 /* Fatal error in PNG image of libpng - can't continue */
 PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
+#  define png_error(s1,s2) png_err(s1)
+#  define png_chunk_error(s1,s2) png_err(s1)
 #endif

 #ifdef PNG_WARNINGS_SUPPORTED
@@ -2007,6 +1953,9 @@ PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
 /* Non-fatal error in libpng, chunk name is prepended to message. */
 PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
    png_const_charp warning_message));
+#else
+#  define png_warning(s1,s2) ((void)(s1))
+#  define png_chunk_warning(s1,s2) ((void)(s1))
 #endif

 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
@@ -2124,7 +2073,7 @@ PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
 PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
    (png_const_structrp png_ptr, png_const_inforp info_ptr));

-#endif /* PNG_EASY_ACCESS_SUPPORTED */
+#endif /* EASY_ACCESS */

 #ifdef PNG_READ_SUPPORTED
 /* Returns pointer to signature string read from PNG header */
@@ -2376,7 +2325,7 @@ PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
 PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
    png_inforp info_ptr, int unit,
    png_const_charp swidth, png_const_charp sheight));
-#endif /* PNG_sCAL_SUPPORTED */
+#endif /* sCAL */

 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
 /* Provide the default handling for all unknown chunks or, optionally, for
@@ -2517,11 +2466,15 @@ PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,

 #ifdef PNG_INFO_IMAGE_SUPPORTED
 /* The "params" pointer is currently not used and is for future expansion. */
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
    int transforms, png_voidp params));
+#endif
+#ifdef PNG_WRITE_SUPPORTED
 PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
    int transforms, png_voidp params));
 #endif
+#endif

 PNG_EXPORT(180, png_const_charp, png_get_copyright,
    (png_const_structrp png_ptr));
@@ -2600,8 +2553,8 @@ PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
 PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
    png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
    int *unit_type));
-#  endif /* PNG_pHYs_SUPPORTED */
-#endif  /* PNG_INCH_CONVERSIONS_SUPPORTED */
+#  endif /* pHYs */
+#endif  /* INCH_CONVERSIONS */

 /* Added in libpng-1.4.0 */
 #ifdef PNG_IO_STATE_SUPPORTED
@@ -2624,7 +2577,7 @@ PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
 #  define PNG_IO_CHUNK_CRC   0x0080   /* currently at the chunk crc */
 #  define PNG_IO_MASK_OP     0x000f   /* current operation: reading/writing */
 #  define PNG_IO_MASK_LOC    0x00f0   /* current location: sig/hdr/data/crc */
-#endif /* ?PNG_IO_STATE_SUPPORTED */
+#endif /* IO_STATE */

 /* Interlace support.  The following macros are always defined so that if
 * libpng interlace handling is turned off the macros may be used to handle
@@ -2728,7 +2681,7 @@ PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
     (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
     (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) +         \
     32767) / 65535)
-#endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
+#endif /* READ_COMPOSITE_NODIV */

 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
@@ -2798,6 +2751,8 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
 #  endif
 #endif

+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
+    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
 /*******************************************************************************
 *  SIMPLIFIED API
 *******************************************************************************
@@ -2869,7 +2824,7 @@ typedef struct
 #  define PNG_IMAGE_WARNING 1
 #  define PNG_IMAGE_ERROR 2
   /*
-    * The result is a two bit code such that a value more than 1 indicates
+    * The result is a two-bit code such that a value more than 1 indicates
    * a failure in the API just called:
    *
    *    0 - no warning or error
@@ -3154,7 +3109,7 @@ PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
 PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
   FILE* file));
   /* The PNG header is read from the stdio FILE object. */
-#endif /* PNG_STDIO_SUPPORTED */
+#endif /* STDIO */

 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
   png_const_voidp memory, png_size_t size));
@@ -3199,7 +3154,7 @@ PNG_EXPORT(238, void, png_image_free, (png_imagep image));
   /* Free any data allocated by libpng in image->opaque, setting the pointer to
    * NULL.  May be called at any time after the structure is initialized.
    */
-#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
+#endif /* SIMPLIFIED_READ */

 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
 #ifdef PNG_STDIO_SUPPORTED
@@ -3245,11 +3200,12 @@ PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
 *
 * Note that the write API does not support interlacing or sub-8-bit pixels.
 */
-#endif /* PNG_STDIO_SUPPORTED */
-#endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */
+#endif /* STDIO */
+#endif /* SIMPLIFIED_WRITE */
 /*******************************************************************************
 *  END OF SIMPLIFIED API
 ******************************************************************************/
+#endif /* SIMPLIFIED_{READ|WRITE} */

 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
 PNG_EXPORT(242, void, png_set_check_for_invalid_index,
@@ -3286,7 +3242,8 @@ PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
 #  define PNG_ARM_NEON   0 /* HARDWARE: ARM Neon SIMD instructions supported */
 #endif
 #define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
-#define PNG_OPTION_NEXT  4 /* Next option - numbers must be even */
+#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
+#define PNG_OPTION_NEXT  6 /* Next option - numbers must be even */

 /* Return values: NOTE: there are four values and 'off' is *not* zero */
 #define PNG_OPTION_UNSET   0 /* Unset - defaults to off */
@@ -3296,19 +3253,18 @@ PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,

 PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
   int onoff));
-#endif
+#endif /* SET_OPTION */

 /*******************************************************************************
- *  END OF HARDWARE OPTIONS
+ *  END OF HARDWARE AND SOFTWARE OPTIONS
 ******************************************************************************/

-/* Maintainer: Put new public prototypes here ^, in libpng.3, and project
- * defs, scripts/pnglibconf.h, and scripts/pnglibconf.h.prebuilt
+/* Maintainer: Put new public prototypes here ^, in libpng.3, in project
+ * defs, and in scripts/symbols.def.
 */

 /* The last ordinal number (this is the *last* one already used; the next
- * one to use is one more than this.)  Maintainer, remember to add an entry to
- * scripts/symbols.def as well.
+ * one to use is one more than this.)
 */
 #ifdef PNG_EXPORT_LAST_ORDINAL
  PNG_EXPORT_LAST_ORDINAL(244);
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,9 +1,9 @@

 /* pngconf.h - machine configurable file for libpng
 *
- * libpng version 1.6.9beta02 - January 1, 2014
+ * libpng version 1.6.15,November 20, 2014
 *
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -361,7 +361,33 @@
   * version 1.2.41.  Disabling these removes the warnings but may also produce
   * less efficient code.
   */
-#  if defined(__GNUC__)
+#  if defined(__clang__) && defined(__has_attribute)
+     /* Clang defines both __clang__ and __GNUC__. Check __clang__ first. */
+#    if !defined(PNG_USE_RESULT) && __has_attribute(__warn_unused_result__)
+#      define PNG_USE_RESULT __attribute__((__warn_unused_result__))
+#    endif
+#    if !defined(PNG_NORETURN) && __has_attribute(__noreturn__)
+#      define PNG_NORETURN __attribute__((__noreturn__))
+#    endif
+#    if !defined(PNG_ALLOCATED) && __has_attribute(__malloc__)
+#      define PNG_ALLOCATED __attribute__((__malloc__))
+#    endif
+#    if !defined(PNG_DEPRECATED) && __has_attribute(__deprecated__)
+#      define PNG_DEPRECATED __attribute__((__deprecated__))
+#    endif
+#    if !defined(PNG_PRIVATE)
+#      ifdef __has_extension
+#        if __has_extension(attribute_unavailable_with_message)
+#          define PNG_PRIVATE __attribute__((__unavailable__(\
+             "This function is not exported by libpng.")))
+#        endif
+#      endif
+#    endif
+#    ifndef PNG_RESTRICT
+#      define PNG_RESTRICT __restrict
+#    endif
+
+#  elif defined(__GNUC__)
 #    ifndef PNG_USE_RESULT
 #      define PNG_USE_RESULT __attribute__((__warn_unused_result__))
 #    endif
@@ -384,12 +410,12 @@
            __attribute__((__deprecated__))
 #        endif
 #      endif
-#      if ((__GNUC__ != 3) || !defined(__GNUC_MINOR__) || (__GNUC_MINOR__ >= 1))
+#      if ((__GNUC__ > 3) || !defined(__GNUC_MINOR__) || (__GNUC_MINOR__ >= 1))
 #        ifndef PNG_RESTRICT
 #          define PNG_RESTRICT __restrict
 #        endif
-#      endif /*  __GNUC__ == 3.0 */
-#    endif /*  __GNUC__ >= 3 */
+#      endif /* __GNUC__.__GNUC_MINOR__ > 3.0 */
+#    endif /* __GNUC__ >= 3 */

 #  elif defined(_MSC_VER)  && (_MSC_VER >= 1300)
 #    ifndef PNG_USE_RESULT
@@ -419,7 +445,7 @@
 #    ifndef PNG_RESTRICT
 #      define PNG_RESTRICT __restrict
 #    endif
-#  endif /* _MSC_VER */
+#  endif
 #endif /* PNG_PEDANTIC_WARNINGS */

 #ifndef PNG_DEPRECATED
@@ -440,6 +466,7 @@
 #ifndef PNG_RESTRICT
 #  define PNG_RESTRICT    /* The C99 "restrict" feature */
 #endif
+
 #ifndef PNG_FP_EXPORT     /* A floating point API. */
 #  ifdef PNG_FLOATING_POINT_SUPPORTED
 #     define PNG_FP_EXPORT(ordinal, type, name, args)\
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,8 +1,8 @@

 /* pngerror.c - stub functions for i/o and memory allocation
 *
- * Last changed in libpng 1.6.8 [December 19, 2013]
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -27,7 +27,7 @@ static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr,
 static void /* PRIVATE */
 png_default_warning PNGARG((png_const_structrp png_ptr,
   png_const_charp warning_message));
-#endif /* PNG_WARNINGS_SUPPORTED */
+#endif /* WARNINGS */

 /* This function is called whenever there is a fatal error.  This function
 * should not be changed.  If there is a need to handle errors differently,
@@ -43,8 +43,8 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),
   char msg[16];
   if (png_ptr != NULL)
   {
-      if (png_ptr->flags&
-         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
+      if ((png_ptr->flags &
+         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0
      {
         if (*error_message == PNG_LITERAL_SHARP)
         {
@@ -54,7 +54,7 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),
               if (error_message[offset] == ' ')
                  break;

-            if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
+            if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
            {
               int i;
               for (i = 0; i < offset - 1; i++)
@@ -69,7 +69,7 @@ png_error,(png_const_structrp png_ptr, png_const_charp error_message),

      else
      {
-         if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
+         if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
         {
            msg[0] = '0';
            msg[1] = '\0';
@@ -103,7 +103,7 @@ png_err,(png_const_structrp png_ptr),PNG_NORETURN)
      use the default handler, which will not return. */
   png_default_error(png_ptr, "");
 }
-#endif /* PNG_ERROR_TEXT_SUPPORTED */
+#endif /* ERROR_TEXT */

 /* Utility to safely appends strings to a buffer.  This never errors out so
 * error checking is not required in the caller.
@@ -152,7 +152,7 @@ png_format_number(png_const_charp start, png_charp end, int format,
         case PNG_NUMBER_FORMAT_fixed:
            /* Needs five digits (the fraction) */
            mincount = 5;
-            if (output || number % 10 != 0)
+            if (output != 0 || number % 10 != 0)
            {
               *--end = digits[number % 10];
               output = 1;
@@ -189,13 +189,13 @@ png_format_number(png_const_charp start, png_charp end, int format,
      ++count;

      /* Float a fixed number here: */
-      if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start)
+      if ((format == PNG_NUMBER_FORMAT_fixed) && (count == 5) && (end > start))
      {
         /* End of the fraction, but maybe nothing was output?  In that case
          * drop the decimal point.  If the number is a true zero handle that
          * here.
          */
-         if (output)
+         if (output != 0)
            *--end = '.';
         else if (number == 0) /* and !output */
            *--end = '0';
@@ -219,8 +219,8 @@ png_warning(png_const_structrp png_ptr, png_const_charp warning_message)
   if (png_ptr != NULL)
   {
 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
-   if (png_ptr->flags&
-       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
+   if ((png_ptr->flags &
+       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
 #endif
      {
         if (*warning_message == PNG_LITERAL_SHARP)
@@ -355,13 +355,13 @@ png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p,
    */
   png_warning(png_ptr, msg);
 }
-#endif /* PNG_WARNINGS_SUPPORTED */
+#endif /* WARNINGS */

 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
 void PNGAPI
 png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
 {
-   if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
   {
 #     ifdef PNG_READ_SUPPORTED
         if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
@@ -391,7 +391,7 @@ png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
 void /* PRIVATE */
 png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
 {
-  if (png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN)
+  if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
     png_warning(png_ptr, error_message);
  else
     png_error(png_ptr, error_message);
@@ -404,7 +404,7 @@ png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
 void /* PRIVATE */
 png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
 {
-  if (png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN)
+  if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
     png_warning(png_ptr, error_message);
  else
     png_error(png_ptr, error_message);
@@ -415,10 +415,13 @@ png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
 }
 #endif /* BENIGN_ERRORS */

+#define PNG_MAX_ERROR_TEXT 196 /* Currently limited by profile_error in png.c */
+#if defined(PNG_WARNINGS_SUPPORTED) || \
+   (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED))
 /* These utilities are used internally to build an error message that relates
 * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
- * this is used to prefix the message.  The message is limited in length
- * to 63 bytes, the name characters are output as hex digits wrapped in []
+ * which is used to prefix the message.  The message is limited in length
+ * to 63 bytes. The name characters are output as hex digits wrapped in []
 * if the character is invalid.
 */
 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
@@ -427,9 +430,6 @@ static PNG_CONST char png_digit[16] = {
   'A', 'B', 'C', 'D', 'E', 'F'
 };

-#define PNG_MAX_ERROR_TEXT 196 /* Currently limited be profile_error in png.c */
-#if defined(PNG_WARNINGS_SUPPORTED) || \
-   (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED))
 static void /* PRIVATE */
 png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
    error_message)
@@ -442,7 +442,7 @@ png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
      int c = (int)(chunk_name >> ishift) & 0xff;

      ishift -= 8;
-      if (isnonalpha(c))
+      if (isnonalpha(c) != 0)
      {
         buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
@@ -473,7 +473,7 @@ png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
      buffer[iout] = '\0';
   }
 }
-#endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */
+#endif /* WARNINGS || ERROR_TEXT */

 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
 PNG_FUNCTION(void,PNGAPI
@@ -490,7 +490,7 @@ png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message),
      png_error(png_ptr, msg);
   }
 }
-#endif /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */
+#endif /* READ && ERROR_TEXT */

 #ifdef PNG_WARNINGS_SUPPORTED
 void PNGAPI
@@ -506,7 +506,7 @@ png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message)
      png_warning(png_ptr, msg);
   }
 }
-#endif /* PNG_WARNINGS_SUPPORTED */
+#endif /* WARNINGS */

 #ifdef PNG_READ_SUPPORTED
 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
@@ -514,7 +514,7 @@ void PNGAPI
 png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
    error_message)
 {
-   if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
      png_chunk_warning(png_ptr, error_message);

   else
@@ -525,7 +525,7 @@ png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
 #  endif
 }
 #endif
-#endif /* PNG_READ_SUPPORTED */
+#endif /* READ */

 void /* PRIVATE */
 png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
@@ -538,7 +538,7 @@ png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
    * unconditionally does the right thing.
    */
 #  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
 #  endif

 #  ifdef PNG_READ_SUPPORTED
@@ -552,7 +552,7 @@ png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
 #  endif

 #  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
-      else if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
+      else if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
 #  endif

 #  ifdef PNG_WRITE_SUPPORTED
@@ -577,11 +577,12 @@ png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
   char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
   memcpy(msg, fixed_message, fixed_message_ln);
   iin = 0;
-   if (name != NULL) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
-   {
-      msg[fixed_message_ln + iin] = name[iin];
-      ++iin;
-   }
+   if (name != NULL)
+      while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
+      {
+         msg[fixed_message_ln + iin] = name[iin];
+         ++iin;
+      }
   msg[fixed_message_ln + iin] = 0;
   png_error(png_ptr, msg);
 }
@@ -757,8 +758,12 @@ PNG_FUNCTION(void,PNGAPI
 png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
 {
 #ifdef PNG_SETJMP_SUPPORTED
-   if (png_ptr && png_ptr->longjmp_fn && png_ptr->jmp_buf_ptr)
+   if (png_ptr != NULL && png_ptr->longjmp_fn != NULL &&
+       png_ptr->jmp_buf_ptr != NULL)
      png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(val)
 #endif

   /* If control reaches this point, png_longjmp() must not return. The only
@@ -819,7 +824,7 @@ png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message)
 #endif
   PNG_UNUSED(png_ptr) /* Make compiler happy */
 }
-#endif /* PNG_WARNINGS_SUPPORTED */
+#endif /* WARNINGS */

 /* This function is called when the application wants to use another method
 * of handling errors and warnings.  Note that the error function MUST NOT
@@ -876,8 +881,8 @@ png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode)
    * possible to implement without setjmp support just so long as there is some
    * way to handle the error return here:
    */
-PNG_FUNCTION(void /* PRIVATE */,
-png_safe_error,(png_structp png_nonconst_ptr, png_const_charp error_message),
+PNG_FUNCTION(void /* PRIVATE */, (PNGCBAPI
+png_safe_error),(png_structp png_nonconst_ptr, png_const_charp error_message),
   PNG_NORETURN)
 {
   const png_const_structrp png_ptr = png_nonconst_ptr;
@@ -912,7 +917,7 @@ png_safe_error,(png_structp png_nonconst_ptr, png_const_charp error_message),
 }

 #ifdef PNG_WARNINGS_SUPPORTED
-void /* PRIVATE */
+void /* PRIVATE */ PNGCBAPI
 png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message)
 {
   const png_const_structrp png_ptr = png_nonconst_ptr;
@@ -939,7 +944,7 @@ png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg)
   saved_error_buf = image->opaque->error_buf;
   result = setjmp(safe_jmpbuf) == 0;

-   if (result)
+   if (result != 0)
   {

      image->opaque->error_buf = safe_jmpbuf;
@@ -949,10 +954,10 @@ png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg)
   image->opaque->error_buf = saved_error_buf;

   /* And do the cleanup prior to any failure return. */
-   if (!result)
+   if (result == 0)
      png_image_free(image);

   return result;
 }
-#endif /* SIMPLIFIED READ/WRITE */
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */
+#endif /* READ || WRITE */
--- a/pngget.c
+++ b/pngget.c
@@ -1,8 +1,8 @@

 /* pngget.c - retrieval of values from info struct
 *
- * Last changed in libpng 1.6.1 [March 28, 2013]
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -116,7 +116,8 @@ png_get_x_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
   info_ptr)
 {
 #ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
      {
         png_debug1(1, "in %s retrieval function",
             "png_get_x_pixels_per_meter");
@@ -124,6 +125,9 @@ png_get_x_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
         if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
            return (info_ptr->x_pixels_per_unit);
      }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
 #endif

   return (0);
@@ -134,7 +138,8 @@ png_get_y_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
    info_ptr)
 {
 #ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function",
          "png_get_y_pixels_per_meter");
@@ -142,6 +147,9 @@ png_get_y_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
      if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
         return (info_ptr->y_pixels_per_unit);
   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
 #endif

   return (0);
@@ -151,7 +159,8 @@ png_uint_32 PNGAPI
 png_get_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_pixels_per_meter");

@@ -159,6 +168,9 @@ png_get_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp info_ptr)
          info_ptr->x_pixels_per_unit == info_ptr->y_pixels_per_unit)
         return (info_ptr->x_pixels_per_unit);
   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
 #endif

   return (0);
@@ -170,7 +182,8 @@ png_get_pixel_aspect_ratio(png_const_structrp png_ptr, png_const_inforp
   info_ptr)
 {
 #ifdef PNG_READ_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio");

@@ -193,10 +206,11 @@ png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr,
    png_const_inforp info_ptr)
 {
 #ifdef PNG_READ_pHYs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)
-       && info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0
-       && info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX
-       && info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0 &&
+       info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0 &&
+       info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX &&
+       info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
   {
      png_fixed_point res;

@@ -206,7 +220,7 @@ png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr,
       * range of 0..2^31-1; otherwise the cast might overflow.
       */
      if (png_muldiv(&res, (png_int_32)info_ptr->y_pixels_per_unit, PNG_FP_1,
-          (png_int_32)info_ptr->x_pixels_per_unit))
+          (png_int_32)info_ptr->x_pixels_per_unit) != 0)
         return res;
   }
 #else
@@ -222,13 +236,17 @@ png_int_32 PNGAPI
 png_get_x_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns");

      if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
         return (info_ptr->x_offset);
   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
 #endif

   return (0);
@@ -238,13 +256,17 @@ png_int_32 PNGAPI
 png_get_y_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_y_offset_microns");

      if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
         return (info_ptr->y_offset);
   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
 #endif

   return (0);
@@ -254,13 +276,17 @@ png_int_32 PNGAPI
 png_get_x_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_x_offset_pixels");

      if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
         return (info_ptr->x_offset);
   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
 #endif

   return (0);
@@ -270,13 +296,17 @@ png_int_32 PNGAPI
 png_get_y_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
 {
 #ifdef PNG_oFFs_SUPPORTED
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "png_get_y_offset_pixels");

      if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
         return (info_ptr->y_offset);
   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
 #endif

   return (0);
@@ -307,7 +337,7 @@ ppi_from_ppm(png_uint_32 ppm)
    */
   png_fixed_point result;
   if (ppm <= PNG_UINT_31_MAX && png_muldiv(&result, (png_int_32)ppm, 127,
-       5000))
+       5000) != 0)
      return result;

   /* Overflow. */
@@ -393,7 +423,8 @@ png_get_pHYs_dpi(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_uint_32 retval = 0;

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      png_debug1(1, "in %s retrieval function", "pHYs");

@@ -424,12 +455,12 @@ png_get_pHYs_dpi(png_const_structrp png_ptr, png_const_inforp info_ptr,

   return (retval);
 }
-#endif /* PNG_pHYs_SUPPORTED */
-#endif  /* PNG_INCH_CONVERSIONS_SUPPORTED */
+#endif /* pHYs */
+#endif  /* INCH_CONVERSIONS */

 /* png_get_channels really belongs in here, too, but it's been around longer */

-#endif  /* PNG_EASY_ACCESS_SUPPORTED */
+#endif  /* EASY_ACCESS */


 png_byte PNGAPI
@@ -457,8 +488,9 @@ png_uint_32 PNGAPI
 png_get_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
   png_color_16p *background)
 {
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)
-       && background != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_bKGD) != 0 &&
+       background != NULL)
   {
      png_debug1(1, "in %s retrieval function", "bKGD");

@@ -488,7 +520,7 @@ png_get_cHRM(png_const_structrp png_ptr, png_const_inforp info_ptr,
    * consistent.
    */
   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "cHRM");

@@ -529,7 +561,7 @@ png_get_cHRM_XYZ(png_const_structrp png_ptr, png_const_inforp info_ptr,
   double *blue_Z)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "cHRM_XYZ(float)");

@@ -577,7 +609,7 @@ png_get_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
    png_fixed_point *int_blue_Z)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "cHRM_XYZ");

@@ -614,7 +646,7 @@ png_get_cHRM_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "cHRM");

   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
   {
      if (white_x != NULL)
         *white_x = info_ptr->colorspace.end_points_xy.whitex;
@@ -649,7 +681,7 @@ png_get_gAMA_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "gAMA");

   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
      file_gamma != NULL)
   {
      *file_gamma = info_ptr->colorspace.gamma;
@@ -668,7 +700,7 @@ png_get_gAMA(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "gAMA(float)");

   if (png_ptr != NULL && info_ptr != NULL &&
-      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
      file_gamma != NULL)
   {
      *file_gamma = png_float(png_ptr, info_ptr->colorspace.gamma,
@@ -688,8 +720,8 @@ png_get_sRGB(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "sRGB");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB)
-       && file_srgb_intent != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->valid & PNG_INFO_sRGB) != 0 && file_srgb_intent != NULL)
   {
      *file_srgb_intent = info_ptr->colorspace.rendering_intent;
      return (PNG_INFO_sRGB);
@@ -707,9 +739,10 @@ png_get_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "iCCP");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)
-       && name != NULL && compression_type != NULL && profile != NULL &&
-		 proflen != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_iCCP) != 0 &&
+       name != NULL && compression_type != NULL && profile != NULL &&
+           proflen != NULL)
   {
      *name = info_ptr->iccp_name;
      *profile = info_ptr->iccp_profile;
@@ -747,8 +780,8 @@ png_get_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "hIST");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)
-       && hist != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_hIST) != 0 && hist != NULL)
   {
      *hist = info_ptr->hist;
      return (PNG_INFO_hIST);
@@ -803,8 +836,9 @@ png_get_oFFs(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "oFFs");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)
-       && offset_x != NULL && offset_y != NULL && unit_type != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0 &&
+       offset_x != NULL && offset_y != NULL && unit_type != NULL)
   {
      *offset_x = info_ptr->x_offset;
      *offset_y = info_ptr->y_offset;
@@ -824,8 +858,9 @@ png_get_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "pCAL");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)
-       && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pCAL) != 0 &&
+       purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
       nparams != NULL && units != NULL && params != NULL)
   {
      *purpose = info_ptr->pcal_purpose;
@@ -851,7 +886,7 @@ png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, png_fixed_point *width, png_fixed_point *height)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      *unit = info_ptr->scal_unit;
      /*TODO: make this work without FP support; the API is currently eliminated
@@ -874,7 +909,7 @@ png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, double *width, double *height)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      *unit = info_ptr->scal_unit;
      *width = atof(info_ptr->scal_s_width);
@@ -890,7 +925,7 @@ png_get_sCAL_s(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, png_charpp width, png_charpp height)
 {
   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
   {
      *unit = info_ptr->scal_unit;
      *width = info_ptr->scal_s_width;
@@ -912,7 +947,7 @@ png_get_pHYs(png_const_structrp png_ptr, png_const_inforp info_ptr,
   png_debug1(1, "in %s retrieval function", "pHYs");

   if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_pHYs))
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
   {
      if (res_x != NULL)
      {
@@ -943,8 +978,8 @@ png_get_PLTE(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "PLTE");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_PLTE)
-       && palette != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_PLTE) != 0 && palette != NULL)
   {
      *palette = info_ptr->palette;
      *num_palette = info_ptr->num_palette;
@@ -962,8 +997,8 @@ png_get_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "sBIT");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)
-       && sig_bit != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sBIT) != 0 && sig_bit != NULL)
   {
      *sig_bit = &(info_ptr->sig_bit);
      return (PNG_INFO_sBIT);
@@ -1006,8 +1041,8 @@ png_get_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   png_debug1(1, "in %s retrieval function", "tIME");

-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)
-       && mod_time != NULL)
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tIME) != 0 && mod_time != NULL)
   {
      *mod_time = &(info_ptr->mod_time);
      return (PNG_INFO_tIME);
@@ -1023,7 +1058,8 @@ png_get_tRNS(png_const_structrp png_ptr, png_inforp info_ptr,
    png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color)
 {
   png_uint_32 retval = 0;
-   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tRNS) != 0)
   {
      png_debug1(1, "in %s retrieval function", "tRNS");

@@ -1100,7 +1136,7 @@ png_get_compression_buffer_size(png_const_structrp png_ptr)
      return 0;

 #  ifdef PNG_WRITE_SUPPORTED
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
 #  endif
   {
 #     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
@@ -1144,7 +1180,7 @@ png_get_chunk_malloc_max (png_const_structrp png_ptr)
 {
   return (png_ptr ? png_ptr->user_chunk_malloc_max : 0);
 }
-#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */
+#endif /* SET_USER_LIMITS */

 /* These functions were added to libpng 1.4.0 */
 #ifdef PNG_IO_STATE_SUPPORTED
@@ -1159,7 +1195,7 @@ png_get_io_chunk_type (png_const_structrp png_ptr)
 {
   return png_ptr->chunk_name;
 }
-#endif /* ?PNG_IO_STATE_SUPPORTED */
+#endif /* IO_STATE */

 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
 #  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
@@ -1174,4 +1210,4 @@ png_get_palette_max(png_const_structp png_ptr, png_const_infop info_ptr)
 #  endif
 #endif

-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* READ || WRITE */
--- a/pnginfo.h
+++ b/pnginfo.h
@@ -121,7 +121,7 @@ struct png_info_def
   int num_text; /* number of comments read or comments to write */
   int max_text; /* current size of text array */
   png_textp text; /* array of comments read or comments to write */
-#endif /* PNG_TEXT_SUPPORTED */
+#endif /* TEXT */

 #ifdef PNG_tIME_SUPPORTED
   /* The tIME chunk holds the last time the displayed image data was
--- a/pngmem.c
+++ b/pngmem.c
@@ -1,8 +1,8 @@

 /* pngmem.c - stub functions for memory allocation
 *
- * Last changed in libpng 1.6.8 [December 19, 2013]
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -199,7 +199,7 @@ png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),

   return ret;
 }
-#endif /* PNG_USER_MEM_SUPPORTED */
+#endif /* USER_MEM */

 /* This function was added at libpng version 1.2.3.  The png_malloc_warn()
 * function will issue a png_warning and return NULL instead of issuing a
@@ -244,7 +244,7 @@ png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED)
 {
   if (png_ptr == NULL || ptr == NULL)
      return;
-#endif /* PNG_USER_MEM_SUPPORTED */
+#endif /* USER_MEM */

   free(ptr);
 }
@@ -277,5 +277,5 @@ png_get_mem_ptr(png_const_structrp png_ptr)

   return png_ptr->mem_ptr;
 }
-#endif /* PNG_USER_MEM_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* USER_MEM */
+#endif /* READ || WRITE */
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,8 +1,8 @@

 /* pngpread.c - read a png file in push mode
 *
- * Last changed in libpng 1.6.8 [December 19, 2013]
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -26,6 +26,13 @@
 #define PNG_READ_iTXt_MODE  7
 #define PNG_ERROR_MODE      8

+#define PNG_PUSH_SAVE_BUFFER_IF_FULL \
+if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
+   { png_push_save_buffer(png_ptr); return; }
+#define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
+if (png_ptr->buffer_size < N) \
+   { png_push_save_buffer(png_ptr); return; }
+
 void PNGAPI
 png_process_data(png_structrp png_ptr, png_inforp info_ptr,
    png_bytep buffer, png_size_t buffer_size)
@@ -46,10 +53,10 @@ png_process_data_pause(png_structrp png_ptr, int save)
 {
   if (png_ptr != NULL)
   {
-      /* It's easiest for the caller if we do the save, then the caller doesn't
+      /* It's easiest for the caller if we do the save; then the caller doesn't
       * have to supply the same data again:
       */
-      if (save)
+      if (save != 0)
         png_push_save_buffer(png_ptr);
      else
      {
@@ -189,23 +196,18 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
   int keep; /* unknown handling method */
 #endif

-   /* First we make sure we have enough data for the 4 byte chunk name
-    * and the 4 byte chunk length before proceeding with decoding the
+   /* First we make sure we have enough data for the 4-byte chunk name
+    * and the 4-byte chunk length before proceeding with decoding the
    * chunk data.  To fully decode each of these chunks, we also make
-    * sure we have enough data in the buffer for the 4 byte CRC at the
+    * sure we have enough data in the buffer for the 4-byte CRC at the
    * end of every chunk (except IDAT, which is handled separately).
    */
-   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

-      if (png_ptr->buffer_size < 8)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
      png_push_fill_buffer(png_ptr, chunk_length, 4);
      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
      png_reset_crc(png_ptr);
@@ -219,27 +221,28 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)

   if (chunk_name == png_IDAT)
   {
-      if (png_ptr->mode & PNG_AFTER_IDAT)
+      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;

      /* If we reach an IDAT chunk, this means we have read all of the
       * header chunks, and we can start reading the image (or if this
       * is called after the image has been read - we have an error).
       */
-      if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
         png_error(png_ptr, "Missing IHDR before IDAT");

      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-          !(png_ptr->mode & PNG_HAVE_PLTE))
+          (png_ptr->mode & PNG_HAVE_PLTE) == 0)
         png_error(png_ptr, "Missing PLTE before IDAT");

      png_ptr->mode |= PNG_HAVE_IDAT;
+      png_ptr->process_mode = PNG_READ_IDAT_MODE;

-      if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+      if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
         if (png_ptr->push_length == 0)
            return;

-      if (png_ptr->mode & PNG_AFTER_IDAT)
+      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
         png_benign_error(png_ptr, "Too many IDATs found");
   }

@@ -248,23 +251,13 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
      if (png_ptr->push_length != 13)
         png_error(png_ptr, "Invalid IHDR length");

-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
   }

   else if (chunk_name == png_IEND)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);

      png_ptr->process_mode = PNG_READ_DONE_MODE;
@@ -274,12 +267,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);

      if (chunk_name == png_PLTE)
@@ -289,11 +277,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)

   else if (chunk_name == png_PLTE)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -312,12 +296,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_gAMA_SUPPORTED
   else if (png_ptr->chunk_name == png_gAMA)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -325,12 +304,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sBIT_SUPPORTED
   else if (png_ptr->chunk_name == png_sBIT)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -338,12 +312,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_cHRM_SUPPORTED
   else if (png_ptr->chunk_name == png_cHRM)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -351,12 +320,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sRGB_SUPPORTED
   else if (chunk_name == png_sRGB)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -364,12 +328,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_iCCP_SUPPORTED
   else if (png_ptr->chunk_name == png_iCCP)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -377,12 +336,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sPLT_SUPPORTED
   else if (chunk_name == png_sPLT)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -390,12 +344,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_tRNS_SUPPORTED
   else if (chunk_name == png_tRNS)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -403,12 +352,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_bKGD_SUPPORTED
   else if (chunk_name == png_bKGD)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -416,12 +360,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_hIST_SUPPORTED
   else if (chunk_name == png_hIST)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -429,12 +368,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_pHYs_SUPPORTED
   else if (chunk_name == png_pHYs)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -442,12 +376,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_oFFs_SUPPORTED
   else if (chunk_name == png_oFFs)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
   }
 #endif
@@ -455,12 +384,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_pCAL_SUPPORTED
   else if (chunk_name == png_pCAL)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -468,12 +392,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_sCAL_SUPPORTED
   else if (chunk_name == png_sCAL)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -481,12 +400,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_tIME_SUPPORTED
   else if (chunk_name == png_tIME)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -494,12 +408,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_tEXt_SUPPORTED
   else if (chunk_name == png_tEXt)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -507,12 +416,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_zTXt_SUPPORTED
   else if (chunk_name == png_zTXt)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
   }

@@ -520,23 +424,14 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_READ_iTXt_SUPPORTED
   else if (chunk_name == png_iTXt)
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
   }
 #endif

   else
   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
         PNG_HANDLE_CHUNK_AS_DEFAULT);
   }
@@ -554,7 +449,7 @@ png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
 void /* PRIVATE */
 png_push_crc_finish(png_structrp png_ptr)
 {
-   if (png_ptr->skip_length && png_ptr->save_buffer_size)
+   if (png_ptr->skip_length != 0 && png_ptr->save_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->save_buffer_size;
      png_uint_32 skip_length = png_ptr->skip_length;
@@ -578,7 +473,7 @@ png_push_crc_finish(png_structrp png_ptr)
      png_ptr->save_buffer_size -= save_size;
      png_ptr->save_buffer_ptr += save_size;
   }
-   if (png_ptr->skip_length && png_ptr->current_buffer_size)
+   if (png_ptr->skip_length != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->current_buffer_size;
      png_uint_32 skip_length = png_ptr->skip_length;
@@ -599,14 +494,9 @@ png_push_crc_finish(png_structrp png_ptr)
      png_ptr->current_buffer_size -= save_size;
      png_ptr->current_buffer_ptr += save_size;
   }
-   if (!png_ptr->skip_length)
+   if (png_ptr->skip_length == 0)
   {
-      if (png_ptr->buffer_size < 4)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
      png_crc_finish(png_ptr, 0);
      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
   }
@@ -621,7 +511,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
      return;

   ptr = buffer;
-   if (png_ptr->save_buffer_size)
+   if (png_ptr->save_buffer_size != 0)
   {
      png_size_t save_size;

@@ -638,7 +528,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
      png_ptr->save_buffer_size -= save_size;
      png_ptr->save_buffer_ptr += save_size;
   }
-   if (length && png_ptr->current_buffer_size)
+   if (length != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size;

@@ -658,7 +548,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 void /* PRIVATE */
 png_push_save_buffer(png_structrp png_ptr)
 {
-   if (png_ptr->save_buffer_size)
+   if (png_ptr->save_buffer_size != 0)
   {
      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
      {
@@ -694,11 +584,13 @@ png_push_save_buffer(png_structrp png_ptr)
      if (png_ptr->save_buffer == NULL)
      {
         png_free(png_ptr, old_buffer);
+         old_buffer = NULL;
         png_error(png_ptr, "Insufficient memory for save_buffer");
      }

      memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
      png_free(png_ptr, old_buffer);
+      old_buffer = NULL;
      png_ptr->save_buffer_max = new_max;
   }
   if (png_ptr->current_buffer_size)
@@ -725,18 +617,13 @@ png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
 void /* PRIVATE */
 png_push_read_IDAT(png_structrp png_ptr)
 {
-   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
   {
      png_byte chunk_length[4];
      png_byte chunk_tag[4];

      /* TODO: this code can be commoned up with the same code in push_read */
-      if (png_ptr->buffer_size < 8)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
      png_push_fill_buffer(png_ptr, chunk_length, 4);
      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
      png_reset_crc(png_ptr);
@@ -748,7 +635,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      {
         png_ptr->process_mode = PNG_READ_CHUNK_MODE;

-         if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
+         if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
            png_error(png_ptr, "Not enough compressed data");

         return;
@@ -757,7 +644,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->idat_size = png_ptr->push_length;
   }

-   if (png_ptr->idat_size && png_ptr->save_buffer_size)
+   if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->save_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;
@@ -784,7 +671,7 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->save_buffer_ptr += save_size;
   }

-   if (png_ptr->idat_size && png_ptr->current_buffer_size)
+   if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
   {
      png_size_t save_size = png_ptr->current_buffer_size;
      png_uint_32 idat_size = png_ptr->idat_size;
@@ -809,14 +696,9 @@ png_push_read_IDAT(png_structrp png_ptr)
      png_ptr->current_buffer_size -= save_size;
      png_ptr->current_buffer_ptr += save_size;
   }
-   if (!png_ptr->idat_size)
+   if (png_ptr->idat_size == 0)
   {
-      if (png_ptr->buffer_size < 4)
-      {
-         png_push_save_buffer(png_ptr);
-         return;
-      }
-
+      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
      png_crc_finish(png_ptr, 0);
      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
      png_ptr->mode |= PNG_AFTER_IDAT;
@@ -961,7 +843,7 @@ png_push_process_row(png_structrp png_ptr)
   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);

 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
-   if (png_ptr->transformations)
+   if (png_ptr->transformations != 0)
      png_do_read_transformations(png_ptr, &row_info);
 #endif

@@ -978,15 +860,16 @@ png_push_process_row(png_structrp png_ptr)


 #ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Blow up interlaced rows to full size */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
+   /* Expand interlaced rows to full size */
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      if (png_ptr->pass < 6)
         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
            png_ptr->transformations);

-    switch (png_ptr->pass)
-    {
+      switch (png_ptr->pass)
+      {
         case 0:
         {
            int i;
@@ -1153,7 +1036,6 @@ png_push_process_row(png_structrp png_ptr)
      }
   }
   else
-#endif
   {
      png_push_have_row(png_ptr, png_ptr->row_buf + 1);
      png_read_push_finish_row(png_ptr);
@@ -1163,7 +1045,6 @@ png_push_process_row(png_structrp png_ptr)
 void /* PRIVATE */
 png_read_push_finish_row(png_structrp png_ptr)
 {
-#ifdef PNG_READ_INTERLACING_SUPPORTED
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */

   /* Start of interlace block */
@@ -1188,8 +1069,7 @@ png_read_push_finish_row(png_structrp png_ptr)
   if (png_ptr->row_number < png_ptr->num_rows)
      return;

-#ifdef PNG_READ_INTERLACING_SUPPORTED
-   if (png_ptr->interlaced)
+   if (png_ptr->interlaced != 0)
   {
      png_ptr->row_number = 0;
      memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
@@ -1213,7 +1093,7 @@ png_read_push_finish_row(png_structrp png_ptr)
             png_pass_start[png_ptr->pass]) /
             png_pass_inc[png_ptr->pass];

-         if (png_ptr->transformations & PNG_INTERLACE)
+         if ((png_ptr->transformations & PNG_INTERLACE) != 0)
            break;

         png_ptr->num_rows = (png_ptr->height +
@@ -1223,7 +1103,6 @@ png_read_push_finish_row(png_structrp png_ptr)

      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
   }
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
 }

 void /* PRIVATE */
@@ -1248,7 +1127,6 @@ png_push_have_row(png_structrp png_ptr, png_bytep row)
         (int)png_ptr->pass);
 }

-#ifdef PNG_READ_INTERLACING_SUPPORTED
 void PNGAPI
 png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
    png_const_bytep new_row)
@@ -1261,9 +1139,8 @@ png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
    * it must be png_ptr->row_buf+1
    */
   if (new_row != NULL)
-      png_combine_row(png_ptr, old_row, 1/*display*/);
+      png_combine_row(png_ptr, old_row, 1/*blocky display*/);
 }
-#endif /* PNG_READ_INTERLACING_SUPPORTED */

 void PNGAPI
 png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
@@ -1288,4 +1165,4 @@ png_get_progressive_ptr(png_const_structrp png_ptr)

   return png_ptr->io_ptr;
 }
-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+#endif /* PROGRESSIVE_READ */
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -6,7 +6,7 @@
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
- * Last changed in libpng 1.6.9 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.10 [March 6, 1014]]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -119,8 +119,12 @@
    * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail
    * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
    * off.
+    *
+    * Note that gcc-4.9 defines __ARM_NEON instead of __ARM_NEON__, so we
+    * check both variants.
    */
-#  if defined(__ARM_NEON__) && defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+#  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
+   defined(PNG_ALIGNED_MEMORY_SUPPORTED)
 #     define PNG_ARM_NEON_OPT 2
 #  else
 #     define PNG_ARM_NEON_OPT 0
@@ -148,7 +152,7 @@
    * libpng implementation list for incorporation in the next minor release.
    */
 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
-#     ifdef __ARM_NEON__
+#     if defined(__ARM_NEON__) || defined(__ARM_NEON)
 #        if defined(__clang__)
            /* At present it is unknown by the libpng developers which versions
             * of clang support the intrinsics, however some or perhaps all
@@ -168,7 +172,7 @@
          */
 #        define PNG_ARM_NEON_IMPLEMENTATION 2
 #     endif /* __ARM_NEON__ */
-#  endif /* !defined PNG_ARM_NEON_IMPLEMENTATION */
+#  endif /* !PNG_ARM_NEON_IMPLEMENTATION */

 #  ifndef PNG_ARM_NEON_IMPLEMENTATION
      /* Use the intrinsics code by default. */
@@ -254,6 +258,11 @@
      extern PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
 #endif

+#ifndef PNG_INTERNAL_CALLBACK
+#  define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
+      extern PNG_FUNCTION(type, (PNGCBAPI name), args, PNG_EMPTY attributes)
+#endif
+
 /* If floating or fixed point APIs are disabled they may still be compiled
 * internally.  To handle this make sure they are declared as the appropriate
 * internal extern function (otherwise the symbol prefixing stuff won't work and
@@ -373,8 +382,6 @@
 #ifdef PNG_WARNINGS_SUPPORTED
 #  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
 #else
-#  define png_warning(s1,s2) ((void)(s1))
-#  define png_chunk_warning(s1,s2) ((void)(s1))
 #  define png_warning_parameter(p,number,string) ((void)0)
 #  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
 #  define png_warning_parameter_signed(p,number,format,value) ((void)0)
@@ -382,8 +389,6 @@
 #  define PNG_WARNING_PARAMETERS(p)
 #endif
 #ifndef PNG_ERROR_TEXT_SUPPORTED
-#  define png_error(s1,s2) png_err(s1)
-#  define png_chunk_error(s1,s2) png_err(s1)
 #  define png_fixed_error(s1,s2) png_err(s1)
 #endif

@@ -821,7 +826,7 @@
    * zlib version number and because this affects handling of certain broken
    * PNG files the -I directives must match.
    *
-    * The most likely explanation is that you passed a -I in CFLAGS, this will
+    * The most likely explanation is that you passed a -I in CFLAGS. This will
    * not work; all the preprocessor directories and in particular all the -I
    * directives must be in CPPFLAGS.
    */
@@ -850,7 +855,7 @@ PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
   /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
    * encoded value with maximum error 0.646365.  Note that the input is not a
    * 16-bit value; it has been multiplied by 255! */
-#endif /* PNG_SIMPLIFIED_READ/WRITE */
+#endif /* SIMPLIFIED_READ/WRITE */


 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
@@ -1085,7 +1090,7 @@ PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,

 #ifdef PNG_WRITE_zTXt_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
-    key, png_const_charp text, png_size_t text_len, int compression),PNG_EMPTY);
+    key, png_const_charp text, int compression),PNG_EMPTY);
 #endif

 #ifdef PNG_WRITE_iTXt_SUPPORTED
@@ -1224,7 +1229,7 @@ PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
 PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
   PNG_EMPTY);
   /* Finish a row while reading, dealing with interlacing passes, etc. */
-#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
+#endif /* SEQUENTIAL_READ */

 /* Initialize the row buffers, etc. */
 PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
@@ -1300,7 +1305,7 @@ PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
 #ifdef PNG_READ_iCCP_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif /* PNG_READ_iCCP_SUPPORTED */
+#endif /* READ_iCCP */

 #ifdef PNG_READ_iTXt_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
@@ -1335,7 +1340,7 @@ PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
 #ifdef PNG_READ_sPLT_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
-#endif /* PNG_READ_sPLT_SUPPORTED */
+#endif /* READ_sPLT */

 #ifdef PNG_READ_sRGB_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
@@ -1449,7 +1454,7 @@ PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
    png_inforp info_ptr),PNG_EMPTY);
 #  endif

-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+#endif /* PROGRESSIVE_READ */

 /* Added at libpng version 1.6.0 */
 #ifdef PNG_GAMMA_SUPPORTED
@@ -1883,11 +1888,11 @@ typedef struct png_control
 * errors that might occur.  Returns true on success, false on failure (either
 * of the function or as a result of a png_error.)
 */
-PNG_INTERNAL_FUNCTION(void,png_safe_error,(png_structp png_ptr,
+PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
   png_const_charp error_message),PNG_NORETURN);

 #ifdef PNG_WARNINGS_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_safe_warning,(png_structp png_ptr,
+PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
   png_const_charp warning_message),PNG_EMPTY);
 #else
 #  define png_safe_warning 0/*dummy argument*/
--- a/pngread.c
+++ b/pngread.c
--- a/pngrio.c
+++ b/pngrio.c
@@ -1,7 +1,7 @@

 /* pngrio.c - functions for data input
 *
- * Last changed in libpng 1.6.9 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.15 [November 20, 2014]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -117,4 +117,4 @@ png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr,
   png_ptr->output_flush_fn = NULL;
 #endif
 }
-#endif /* PNG_READ_SUPPORTED */
+#endif /* READ */
--- a/pngrtran.c
+++ b/pngrtran.c
--- a/pngrutil.c
+++ b/pngrutil.c
--- a/pngset.c
+++ b/pngset.c
@@ -1,8 +1,8 @@

 /* pngset.c - storage of image information into info struct
 *
- * Last changed in libpng 1.6.8 [December 19, 2013]
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -59,7 +59,7 @@ png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
   xy.whitey = white_y;

   if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy,
-      2/* override with app values*/))
+       2/* override with app values*/) != 0)
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
@@ -90,7 +90,8 @@ png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
   XYZ.blue_Y = int_blue_Y;
   XYZ.blue_Z = int_blue_Z;

-   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace, &XYZ, 2))
+   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
+       &XYZ, 2) != 0)
      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;

   png_colorspace_sync_info(png_ptr, info_ptr);
@@ -129,9 +130,9 @@ png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X,
      png_fixed(png_ptr, blue_Y, "cHRM Red Y"),
      png_fixed(png_ptr, blue_Z, "cHRM Red Z"));
 }
-#  endif /* PNG_FLOATING_POINT_SUPPORTED */
+#  endif /* FLOATING_POINT */

-#endif /* PNG_cHRM_SUPPORTED */
+#endif /* cHRM */

 #ifdef PNG_gAMA_SUPPORTED
 void PNGFAPI
@@ -227,13 +228,13 @@ png_set_IHDR(png_const_structrp png_ptr, png_inforp info_ptr,
   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      info_ptr->channels = 1;

-   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
+   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
      info_ptr->channels = 3;

   else
      info_ptr->channels = 1;

-   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+   if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      info_ptr->channels++;

   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
@@ -288,12 +289,14 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,

   /* Validate params[nparams] */
   for (i=0; i<nparams; ++i)
+   {
      if (params[i] == NULL ||
-         !png_check_fp_string(params[i], strlen(params[i])))
+          !png_check_fp_string(params[i], strlen(params[i])))
         png_error(png_ptr, "Invalid format for pCAL parameter");
+   }

   info_ptr->pcal_purpose = png_voidcast(png_charp,
-      png_malloc_warn(png_ptr, length));
+       png_malloc_warn(png_ptr, length));

   if (info_ptr->pcal_purpose == NULL)
   {
@@ -594,7 +597,8 @@ png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent))
+   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
+       srgb_intent) != 0)
   {
      /* This causes the gAMA and cHRM to be written too */
      info_ptr->colorspace.flags |=
@@ -637,7 +641,7 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
      png_colorspace_sync_info(png_ptr, info_ptr);

      /* Don't do any of the copying if the profile was bad, or inconsistent. */
-      if (!result)
+      if (result == 0)
         return;

      /* But do write the gAMA and cHRM chunks from the profile. */
@@ -661,6 +665,7 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
   if (new_iccp_profile == NULL)
   {
      png_free(png_ptr, new_iccp_name);
+      new_iccp_name = NULL;
      png_benign_error(png_ptr,
          "Insufficient memory to process iCCP profile");
      return;
@@ -686,7 +691,7 @@ png_set_text(png_const_structrp png_ptr, png_inforp info_ptr,
   int ret;
   ret = png_set_text_2(png_ptr, info_ptr, text_ptr, num_text);

-   if (ret)
+   if (ret != 0)
      png_error(png_ptr, "Insufficient memory to store text");
 }

@@ -726,7 +731,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
         else
            max_text = INT_MAX;

-         /* Now allocate a new array and copy the old members in, this does all
+         /* Now allocate a new array and copy the old members in; this does all
          * the overflow checks.
          */
         new_text = png_voidcast(png_textp,png_realloc_array(png_ptr,
@@ -855,7 +860,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
         textp->text = textp->key + key_len + 1;
      }

-      if (text_length)
+      if (text_length != 0)
         memcpy(textp->text, text_ptr[i].text, text_length);

      *(textp->text + text_length) = '\0';
@@ -890,7 +895,7 @@ png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
   png_debug1(1, "in %s storage function", "tIME");

   if (png_ptr == NULL || info_ptr == NULL || mod_time == NULL ||
-       (png_ptr->mode & PNG_WROTE_tIME))
+       (png_ptr->mode & PNG_WROTE_tIME) != 0)
      return;

   if (mod_time->month == 0   || mod_time->month > 12  ||
@@ -1020,8 +1025,8 @@ png_set_sPLT(png_const_structrp png_ptr,

      np->depth = entries->depth;

-      /* In the even of out-of-memory just return - there's no point keeping on
-       * trying to add sPLT chunks.
+      /* In the event of out-of-memory just return - there's no point keeping
+       * on trying to add sPLT chunks.
       */
      length = strlen(entries->name) + 1;
      np->name = png_voidcast(png_charp, png_malloc_base(png_ptr, length));
@@ -1032,8 +1037,8 @@ png_set_sPLT(png_const_structrp png_ptr,
      memcpy(np->name, entries->name, length);

      /* IMPORTANT: we have memory now that won't get freed if something else
-       * goes wrong, this code must free it.  png_malloc_array produces no
-       * warnings, use a png_chunk_report (below) if there is an error.
+       * goes wrong; this code must free it.  png_malloc_array produces no
+       * warnings; use a png_chunk_report (below) if there is an error.
       */
      np->entries = png_voidcast(png_sPLT_entryp, png_malloc_array(png_ptr,
          entries->nentries, sizeof (png_sPLT_entry)));
@@ -1041,6 +1046,7 @@ png_set_sPLT(png_const_structrp png_ptr,
      if (np->entries == NULL)
      {
         png_free(png_ptr, np->name);
+         np->name = NULL;
         break;
      }

@@ -1063,7 +1069,7 @@ png_set_sPLT(png_const_structrp png_ptr,
   if (nentries > 0)
      png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
 }
-#endif /* PNG_sPLT_SUPPORTED */
+#endif /* sPLT */

 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
 static png_byte
@@ -1072,10 +1078,10 @@ check_location(png_const_structrp png_ptr, int location)
   location &= (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT);

   /* New in 1.6.0; copy the location and check it.  This is an API
-    * change, previously the app had to use the
+    * change; previously the app had to use the
    * png_set_unknown_chunk_location API below for each chunk.
    */
-   if (location == 0 && !(png_ptr->mode & PNG_IS_READ_STRUCT))
+   if (location == 0 && (png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
   {
      /* Write struct, so unknown chunks come from the app */
      png_app_warning(png_ptr,
@@ -1121,7 +1127,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
    */
 #  if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_READ_SUPPORTED)
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
      {
         png_app_error(png_ptr, "no unknown chunk support on read");
         return;
@@ -1129,7 +1135,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
 #  endif
 #  if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \
      defined(PNG_WRITE_SUPPORTED)
-      if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
      {
         png_app_error(png_ptr, "no unknown chunk support on write");
         return;
@@ -1215,7 +1221,7 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
      {
         png_app_error(png_ptr, "invalid unknown chunk location");
         /* Fake out the pre 1.6.0 behavior: */
-         if ((location & PNG_HAVE_IDAT)) /* undocumented! */
+         if ((location & PNG_HAVE_IDAT) != 0) /* undocumented! */
            location = PNG_AFTER_IDAT;

         else
@@ -1253,10 +1259,13 @@ add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep)
   /* Utility function: update the 'keep' state of a chunk if it is already in
    * the list, otherwise add it to the list.
    */
-   for (i=0; i<count; ++i, list += 5) if (memcmp(list, add, 4) == 0)
+   for (i=0; i<count; ++i, list += 5)
   {
-      list[4] = (png_byte)keep;
-      return count;
+      if (memcmp(list, add, 4) == 0)
+      {
+         list[4] = (png_byte)keep;
+         return count;
+      }
   }

   if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
@@ -1320,7 +1329,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
      };

      chunk_list = chunks_to_ignore;
-      num_chunks = (sizeof chunks_to_ignore)/5;
+      num_chunks = (unsigned int)/*SAFE*/(sizeof chunks_to_ignore)/5U;
   }

   else /* num_chunks_in > 0 */
@@ -1353,7 +1362,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
    * required because add_one_chunk above doesn't extend the list if the 'keep'
    * parameter is the default.
    */
-   if (keep)
+   if (keep != 0)
   {
      new_list = png_voidcast(png_bytep, png_malloc(png_ptr,
          5 * (num_chunks + old_num_chunks)));
@@ -1380,12 +1389,15 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
      unsigned int i;

      for (i=0; i<num_chunks; ++i)
+      {
         old_num_chunks = add_one_chunk(new_list, old_num_chunks,
            chunk_list+5*i, keep);
+      }

      /* Now remove any spurious 'default' entries. */
      num_chunks = 0;
      for (i=0, inlist=outlist=new_list; i<old_num_chunks; ++i, inlist += 5)
+      {
         if (inlist[4])
         {
            if (outlist != inlist)
@@ -1393,6 +1405,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
            outlist += 5;
            ++num_chunks;
         }
+      }

      /* This means the application has removed all the specialized handling. */
      if (num_chunks == 0)
@@ -1444,12 +1457,13 @@ png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr,
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (info_ptr->row_pointers && (info_ptr->row_pointers != row_pointers))
+   if (info_ptr->row_pointers != NULL &&
+       (info_ptr->row_pointers != row_pointers))
      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);

   info_ptr->row_pointers = row_pointers;

-   if (row_pointers)
+   if (row_pointers != NULL)
      info_ptr->valid |= PNG_INFO_IDAT;
 }
 #endif
@@ -1464,7 +1478,7 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
       png_error(png_ptr, "invalid compression buffer size");

 #  ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-      if (png_ptr->mode & PNG_IS_READ_STRUCT)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
      {
         png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
         return;
@@ -1472,7 +1486,7 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
 #  endif

 #  ifdef PNG_WRITE_SUPPORTED
-      if (!(png_ptr->mode & PNG_IS_READ_STRUCT))
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
      {
         if (png_ptr->zowner != 0)
         {
@@ -1510,7 +1524,7 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
 void PNGAPI
 png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
 {
-   if (png_ptr && info_ptr)
+   if (png_ptr != NULL && info_ptr != NULL)
      info_ptr->valid &= ~mask;
 }

@@ -1536,7 +1550,7 @@ png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max,
 void PNGAPI
 png_set_chunk_cache_max (png_structrp png_ptr, png_uint_32 user_chunk_cache_max)
 {
-    if (png_ptr)
+    if (png_ptr != NULL)
       png_ptr->user_chunk_cache_max = user_chunk_cache_max;
 }

@@ -1545,10 +1559,10 @@ void PNGAPI
 png_set_chunk_malloc_max (png_structrp png_ptr,
    png_alloc_size_t user_chunk_malloc_max)
 {
-   if (png_ptr)
+   if (png_ptr != NULL)
      png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
 }
-#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */
+#endif /* ?SET_USER_LIMITS */


 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
@@ -1563,7 +1577,7 @@ png_set_benign_errors(png_structrp png_ptr, int allowed)
    * is the default behavior if png_set_benign_errors() is not called).
    */

-   if (allowed)
+   if (allowed != 0)
      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN |
         PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN;

@@ -1571,14 +1585,14 @@ png_set_benign_errors(png_structrp png_ptr, int allowed)
      png_ptr->flags &= ~(PNG_FLAG_BENIGN_ERRORS_WARN |
         PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN);
 }
-#endif /* PNG_BENIGN_ERRORS_SUPPORTED */
+#endif /* BENIGN_ERRORS */

 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
   /* Whether to report invalid palette index; added at libng-1.5.10.
    * It is possible for an indexed (color-type==3) PNG file to contain
    * pixels with invalid (out-of-range) indexes if the PLTE chunk has
    * fewer entries than the image's bit-depth would allow. We recover
-    * from this gracefully by filling any incomplete palette with zeroes
+    * from this gracefully by filling any incomplete palette with zeros
    * (opaque black).  By default, when this occurs libpng will issue
    * a benign error.  This API can be used to override that behavior.
    */
@@ -1594,4 +1608,4 @@ png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
      png_ptr->num_palette_max = -1;
 }
 #endif
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* READ || WRITE */
--- a/pngstruct.h
+++ b/pngstruct.h
@@ -274,7 +274,7 @@ struct png_struct_def
 #ifdef PNG_READ_GAMMA_SUPPORTED
   png_color_16 background_1; /* background normalized to gamma 1.0 */
 #endif
-#endif /* PNG_bKGD_SUPPORTED */
+#endif /* bKGD */

 #ifdef PNG_WRITE_FLUSH_SUPPORTED
   png_flush_ptr output_flush_fn; /* Function for flushing output */
@@ -331,7 +331,7 @@ struct png_struct_def
   int process_mode;                 /* what push library is currently doing */
   int cur_palette;                  /* current push library palette index */

-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+#endif /* PROGRESSIVE_READ */

 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
 /* For the Borland special 64K segment handler */
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,7 +1,7 @@

 /* pngtest.c - a simple test program to test libpng
 *
- * Last changed in libpng 1.6.9 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.15 [November 20, 2014]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -283,7 +283,8 @@ count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
       png_uint_32 n, nstop;
       int channel;
       int color_channels = row_info->channels;
-       if (row_info->color_type > 3)color_channels--;
+       if (row_info->color_type > 3)
+          color_channels--;

       for (n = 0, nstop=row_info->width; n<nstop; n++)
       {
@@ -310,7 +311,7 @@ count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
       }
    }
 }
-#endif /* PNG_WRITE_USER_TRANSFORM_SUPPORTED */
+#endif /* WRITE_USER_TRANSFORM */

 #ifndef PNG_STDIO_SUPPORTED
 /* START of code to validate stdio-free compilation */
@@ -359,7 +360,7 @@ pngtest_check_io_state(png_structp png_ptr, png_size_t data_length,
   default:
      err = 1;  /* uninitialized */
   }
-   if (err)
+   if (err != 0)
      png_error(png_ptr, "Bad I/O state or buffer size");
 }
 #endif
@@ -419,7 +420,7 @@ pngtest_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
   pngtest_check_io_state(png_ptr, length, PNG_IO_WRITING);
 #endif
 }
-#endif /* !PNG_STDIO_SUPPORTED */
+#endif /* !STDIO */

 /* This function is called when there is a warning, but the library thinks
 * it can continue anyway.  Replacement functions don't have to do anything
@@ -540,7 +541,7 @@ PNGCBAPI png_debug_malloc(png_structp png_ptr, png_alloc_size_t size)
      /* Make sure the caller isn't assuming zeroed memory. */
      memset(pinfo->pointer, 0xdd, pinfo->size);

-      if (verbose)
+      if (verbose != 0)
         printf("png_malloc %lu bytes at %p\n", (unsigned long)size,
            pinfo->pointer);

@@ -580,7 +581,7 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)
            /* We must free the list element too, but first kill
               the memory that is to be freed. */
            memset(ptr, 0x55, pinfo->size);
-            if (pinfo)
+            if (pinfo != NULL)
               free(pinfo);
            pinfo = NULL;
            break;
@@ -588,7 +589,7 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)

         if (pinfo->next == NULL)
         {
-            fprintf(STDERR, "Pointer %x not found\n", (unsigned int)ptr);
+            fprintf(STDERR, "Pointer %p not found\n", ptr);
            break;
         }

@@ -597,14 +598,14 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)
   }

   /* Finally free the data. */
-   if (verbose)
+   if (verbose != 0)
      printf("Freeing %p\n", ptr);

-   if (ptr)
+   if (ptr != NULL)
      free(ptr);
   ptr = NULL;
 }
-#endif /* PNG_USER_MEM_SUPPORTED && PNG_DEBUG */
+#endif /* USER_MEM && DEBUG */
 /* END of code to test memory allocation/deallocation */


@@ -643,16 +644,16 @@ set_location(png_structp png_ptr, struct user_chunk_data *data, int what)
 {
   int location;

-   if ((data->location[0] & what) || (data->location[1] & what))
+   if ((data->location[0] & what) != 0 || (data->location[1] & what) != 0)
      return 0; /* already have one of these */

-   /* Find where we are (the code below zeros info_ptr to indicate that the
+   /* Find where we are (the code below zeroes info_ptr to indicate that the
    * chunks before the first IDAT have been read.)
    */
   if (data->info_ptr == NULL) /* after IDAT */
      location = what | after_IDAT;

-   else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE))
+   else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE) != 0)
      location = what | before_IDAT;

   else
@@ -667,8 +668,8 @@ set_location(png_structp png_ptr, struct user_chunk_data *data, int what)
   return 1; /* handled */
 }

-static int PNGCBAPI read_user_chunk_callback(png_struct *png_ptr,
-   png_unknown_chunkp chunk)
+static int PNGCBAPI
+read_user_chunk_callback(png_struct *png_ptr, png_unknown_chunkp chunk)
 {
   struct user_chunk_data *my_user_chunk_data =
      (struct user_chunk_data*)png_get_user_chunk_ptr(png_ptr);
@@ -699,7 +700,7 @@ static int PNGCBAPI read_user_chunk_callback(png_struct *png_ptr,
         if (chunk->data[0] != 0 && chunk->data[0] != 1)
            return (-1);  /* Invalid mode */

-         if (set_location(png_ptr, my_user_chunk_data, have_sTER))
+         if (set_location(png_ptr, my_user_chunk_data, have_sTER) != 0)
         {
            my_user_chunk_data->sTER_mode=chunk->data[0];
            return (1);
@@ -718,7 +719,7 @@ static int PNGCBAPI read_user_chunk_callback(png_struct *png_ptr,
   if (chunk->size != 9)
      return (-1); /* Error return */

-   if (!set_location(png_ptr, my_user_chunk_data, have_vpAg))
+   if (set_location(png_ptr, my_user_chunk_data, have_vpAg) == 0)
      return (0);  /* duplicate vpAg */

   my_user_chunk_data->vpAg_width = png_get_uint_31(png_ptr, chunk->data);
@@ -734,7 +735,7 @@ write_sTER_chunk(png_structp write_ptr)
 {
   png_byte sTER[5] = {115,  84,  69,  82, '\0'};

-   if (verbose)
+   if (verbose != 0)
      fprintf(STDERR, "\n stereo mode = %d\n", user_chunk_data.sTER_mode);

   png_write_chunk(write_ptr, sTER, &user_chunk_data.sTER_mode, 1);
@@ -747,7 +748,7 @@ write_vpAg_chunk(png_structp write_ptr)

   png_byte vpag_chunk_data[9];

-   if (verbose)
+   if (verbose != 0)
      fprintf(STDERR, " vpAg = %lu x %lu, units = %d\n",
        (unsigned long)user_chunk_data.vpAg_width,
        (unsigned long)user_chunk_data.vpAg_height,
@@ -779,8 +780,8 @@ write_chunks(png_structp write_ptr, int location)
         write_vpAg_chunk(write_ptr);
   }
 }
-#endif /* PNG_WRITE_SUPPORTED */
-#else /* !PNG_READ_USER_CHUNKS_SUPPORTED */
+#endif /* WRITE */
+#else /* !READ_USER_CHUNKS */
 #  define write_chunks(pp,loc) ((void)0)
 #endif
 /* END of code to demonstrate user chunk support */
@@ -938,7 +939,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
 #endif
 #endif

-   if (strict)
+   if (strict != 0)
   {
      /* Treat png_benign_error() as errors on read */
      png_set_benign_errors(read_ptr, 0);
@@ -954,7 +955,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
       */
   }

-   else if (relaxed)
+   else if (relaxed != 0)
   {
      /* Allow application (pngtest) errors and warnings to pass */
      png_set_benign_errors(read_ptr, 1);
@@ -1049,7 +1050,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int interlace_type, compression_type, filter_type;

      if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth,
-          &color_type, &interlace_type, &compression_type, &filter_type))
+          &color_type, &interlace_type, &compression_type, &filter_type) != 0)
      {
         png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,
            color_type, interlace_type, compression_type, filter_type);
@@ -1082,7 +1083,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         blue_y;

      if (png_get_cHRM_fixed(read_ptr, read_info_ptr, &white_x, &white_y,
-         &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y))
+         &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
      {
         png_set_cHRM_fixed(write_ptr, write_info_ptr, white_x, white_y, red_x,
            red_y, green_x, green_y, blue_x, blue_y);
@@ -1093,7 +1094,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_fixed_point gamma;

-      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma))
+      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma) != 0)
         png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma);
   }
 #endif
@@ -1105,7 +1106,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         blue_y;

      if (png_get_cHRM(read_ptr, read_info_ptr, &white_x, &white_y, &red_x,
-         &red_y, &green_x, &green_y, &blue_x, &blue_y))
+         &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
      {
         png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x,
            red_y, green_x, green_y, blue_x, blue_y);
@@ -1116,7 +1117,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      double gamma;

-      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma))
+      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma) != 0)
         png_set_gAMA(write_ptr, write_info_ptr, gamma);
   }
 #endif
@@ -1130,7 +1131,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int compression_type;

      if (png_get_iCCP(read_ptr, read_info_ptr, &name, &compression_type,
-                      &profile, &proflen))
+                      &profile, &proflen) != 0)
      {
         png_set_iCCP(write_ptr, write_info_ptr, name, compression_type,
                      profile, proflen);
@@ -1141,7 +1142,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      int intent;

-      if (png_get_sRGB(read_ptr, read_info_ptr, &intent))
+      if (png_get_sRGB(read_ptr, read_info_ptr, &intent) != 0)
         png_set_sRGB(write_ptr, write_info_ptr, intent);
   }
 #endif
@@ -1149,14 +1150,14 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_colorp palette;
      int num_palette;

-      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette))
+      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette) != 0)
         png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette);
   }
 #ifdef PNG_bKGD_SUPPORTED
   {
      png_color_16p background;

-      if (png_get_bKGD(read_ptr, read_info_ptr, &background))
+      if (png_get_bKGD(read_ptr, read_info_ptr, &background) != 0)
      {
         png_set_bKGD(write_ptr, write_info_ptr, background);
      }
@@ -1166,7 +1167,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_uint_16p hist;

-      if (png_get_hIST(read_ptr, read_info_ptr, &hist))
+      if (png_get_hIST(read_ptr, read_info_ptr, &hist) != 0)
         png_set_hIST(write_ptr, write_info_ptr, hist);
   }
 #endif
@@ -1176,7 +1177,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int unit_type;

      if (png_get_oFFs(read_ptr, read_info_ptr, &offset_x, &offset_y,
-          &unit_type))
+          &unit_type) != 0)
      {
         png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);
      }
@@ -1190,7 +1191,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int type, nparams;

      if (png_get_pCAL(read_ptr, read_info_ptr, &purpose, &X0, &X1, &type,
-         &nparams, &units, &params))
+         &nparams, &units, &params) != 0)
      {
         png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type,
            nparams, units, params);
@@ -1202,7 +1203,8 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_uint_32 res_x, res_y;
      int unit_type;

-      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y, &unit_type))
+      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y,
+          &unit_type) != 0)
         png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);
   }
 #endif
@@ -1210,7 +1212,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_color_8p sig_bit;

-      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit))
+      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit) != 0)
         png_set_sBIT(write_ptr, write_info_ptr, sig_bit);
   }
 #endif
@@ -1222,7 +1224,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      double scal_width, scal_height;

      if (png_get_sCAL(read_ptr, read_info_ptr, &unit, &scal_width,
-         &scal_height))
+         &scal_height) != 0)
      {
         png_set_sCAL(write_ptr, write_info_ptr, unit, scal_width, scal_height);
      }
@@ -1234,7 +1236,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_charp scal_width, scal_height;

      if (png_get_sCAL_s(read_ptr, read_info_ptr, &unit, &scal_width,
-          &scal_height))
+          &scal_height) != 0)
      {
         png_set_sCAL_s(write_ptr, write_info_ptr, unit, scal_width,
             scal_height);
@@ -1254,7 +1256,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)

         pngtest_check_text_support(read_ptr, text_ptr, num_text);

-         if (verbose)
+         if (verbose != 0)
         {
            int i;

@@ -1274,11 +1276,11 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_timep mod_time;

-      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time))
+      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time) != 0)
      {
         png_set_tIME(write_ptr, write_info_ptr, mod_time);
 #ifdef PNG_TIME_RFC1123_SUPPORTED
-         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time))
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
            tIME_string[(sizeof tIME_string) - 1] = '\0';

         else
@@ -1288,7 +1290,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         }

         tIME_chunk_present++;
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
+#endif /* TIME_RFC1123 */
      }
   }
 #endif
@@ -1299,7 +1301,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      png_color_16p trans_color;

      if (png_get_tRNS(read_ptr, read_info_ptr, &trans_alpha, &num_trans,
-         &trans_color))
+         &trans_color) != 0)
      {
         int sample_max = (1 << bit_depth);
         /* libpng doesn't reject a tRNS chunk with out-of-range samples */
@@ -1320,7 +1322,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int num_unknowns = png_get_unknown_chunks(read_ptr, read_info_ptr,
         &unknowns);

-      if (num_unknowns)
+      if (num_unknowns != 0)
      {
         png_set_unknown_chunks(write_ptr, write_info_ptr, unknowns,
           num_unknowns);
@@ -1382,11 +1384,12 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      {
 #ifndef SINGLE_ROWBUF_ALLOC
         pngtest_debug2("Allocating row buffer (pass %d, y = %u)...", pass, y);
+
         row_buf = (png_bytep)png_malloc(read_ptr,
            png_get_rowbytes(read_ptr, read_info_ptr));

-         pngtest_debug2("\t0x%08lx (%u bytes)", (unsigned long)row_buf,
-            png_get_rowbytes(read_ptr, read_info_ptr));
+         pngtest_debug2("\t0x%08lx (%lu bytes)", (unsigned long)row_buf,
+            (unsigned long)png_get_rowbytes(read_ptr, read_info_ptr));

 #endif /* !SINGLE_ROWBUF_ALLOC */
         png_read_rows(read_ptr, (png_bytepp)&row_buf, NULL, 1);
@@ -1403,7 +1406,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         t_encode += (t_stop - t_start);
         t_start = t_stop;
 #endif
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */

 #ifndef SINGLE_ROWBUF_ALLOC
         pngtest_debug2("Freeing row buffer (pass %d, y = %u)", pass, y);
@@ -1436,7 +1439,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)

         pngtest_check_text_support(read_ptr, text_ptr, num_text);

-         if (verbose)
+         if (verbose != 0)
         {
            int i;

@@ -1456,11 +1459,11 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   {
      png_timep mod_time;

-      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time))
+      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time) != 0)
      {
         png_set_tIME(write_ptr, write_end_info_ptr, mod_time);
 #ifdef PNG_TIME_RFC1123_SUPPORTED
-         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time))
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
            tIME_string[(sizeof tIME_string) - 1] = '\0';

         else
@@ -1470,7 +1473,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         }

         tIME_chunk_present++;
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
+#endif /* TIME_RFC1123 */
      }
   }
 #endif
@@ -1480,7 +1483,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
      int num_unknowns = png_get_unknown_chunks(read_ptr, end_info_ptr,
         &unknowns);

-      if (num_unknowns)
+      if (num_unknowns != 0)
      {
         png_set_unknown_chunks(write_ptr, write_end_info_ptr, unknowns,
           num_unknowns);
@@ -1521,7 +1524,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
 #endif

 #ifdef PNG_EASY_ACCESS_SUPPORTED
-   if (verbose)
+   if (verbose != 0)
   {
      png_uint_32 iwidth, iheight;
      iwidth = png_get_image_width(write_ptr, write_info_ptr);
@@ -1599,7 +1602,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
   }

 #ifdef PNG_WRITE_SUPPORTED /* else nothing was written */
-   if (interlace_preserved) /* else the files will be changed */
+   if (interlace_preserved != 0) /* else the files will be changed */
   {
      for (;;)
      {
@@ -1638,7 +1641,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
              return (0);
         }

-         if (!num_in)
+         if (num_in == 0)
            break;

         if (memcmp(inbuf, outbuf, num_in))
@@ -1675,7 +1678,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
         }
      }
   }
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */

   FCLOSE(fpin);
   FCLOSE(fpout);
@@ -1780,10 +1783,11 @@ main(int argc, char *argv[])
      }
   }

-   if (!multiple && argc == 3 + verbose)
+   if (multiple == 0 && argc == 3 + verbose)
     outname = argv[2 + verbose];

-   if ((!multiple && argc > 3 + verbose) || (multiple && argc < 2))
+   if ((multiple == 0 && argc > 3 + verbose) ||
+       (multiple != 0 && argc < 2))
   {
     fprintf(STDERR,
       "usage: %s [infile.png] [outfile.png]\n\t%s -m {infile.png}\n",
@@ -1795,7 +1799,7 @@ main(int argc, char *argv[])
     exit(1);
   }

-   if (multiple)
+   if (multiple != 0)
   {
      int i;
 #if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
@@ -1805,6 +1809,9 @@ main(int argc, char *argv[])
      {
         int kerror;
         fprintf(STDERR, "\n Testing %s:", argv[i]);
+#if PNG_DEBUG > 0
+         fprintf(STDERR, "\n");
+#endif
         kerror = test_one_file(argv[i], outname);
         if (kerror == 0)
         {
@@ -1819,7 +1826,7 @@ main(int argc, char *argv[])
 #endif
 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
            for (k = 0; k<256; k++)
-               if (filters_used[k])
+               if (filters_used[k] != 0)
                  fprintf(STDERR, " Filter %d was used %lu times\n",
                     k, (unsigned long)filters_used[k]);
 #endif
@@ -1828,7 +1835,7 @@ main(int argc, char *argv[])
            fprintf(STDERR, " tIME = %s\n", tIME_string);

         tIME_chunk_present = 0;
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
+#endif /* TIME_RFC1123 */
         }

         else
@@ -1850,9 +1857,9 @@ main(int argc, char *argv[])

            while (pinfo != NULL)
            {
-               fprintf(STDERR, " %lu bytes at %x\n",
+               fprintf(STDERR, " %lu bytes at %p\n",
                 (unsigned long)pinfo->size,
-                 (unsigned int)pinfo->pointer);
+                 pinfo->pointer);
               pinfo = pinfo->next;
            }
         }
@@ -1886,7 +1893,12 @@ main(int argc, char *argv[])
            status_dots_requested = 0;

         if (i == 0 || verbose == 1 || ierror != 0)
+         {
            fprintf(STDERR, "\n Testing %s:", inname);
+#if PNG_DEBUG > 0
+            fprintf(STDERR, "\n");
+#endif
+         }

         kerror = test_one_file(inname, outname);

@@ -1905,21 +1917,26 @@ main(int argc, char *argv[])
 #endif
 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
                for (k = 0; k<256; k++)
-                   if (filters_used[k])
+                   if (filters_used[k] != 0)
                      fprintf(STDERR, " Filter %d was used %lu times\n",
                         k, (unsigned long)filters_used[k]);
 #endif
 #ifdef PNG_TIME_RFC1123_SUPPORTED
             if (tIME_chunk_present != 0)
                fprintf(STDERR, " tIME = %s\n", tIME_string);
-#endif /* PNG_TIME_RFC1123_SUPPORTED */
+#endif /* TIME_RFC1123 */
            }
         }

         else
         {
            if (verbose == 0 && i != 2)
+            {
               fprintf(STDERR, "\n Testing %s:", inname);
+#if PNG_DEBUG > 0
+               fprintf(STDERR, "\n");
+#endif
+            }

            fprintf(STDERR, " FAIL\n");
            ierror += kerror;
@@ -1938,8 +1955,8 @@ main(int argc, char *argv[])

             while (pinfo != NULL)
             {
-                fprintf(STDERR, " %lu bytes at %x\n",
-                   (unsigned long)pinfo->size, (unsigned int)pinfo->pointer);
+                fprintf(STDERR, " %lu bytes at %p\n",
+                   (unsigned long)pinfo->size, pinfo->pointer);
                pinfo = pinfo->next;
             }
          }
@@ -1991,4 +2008,4 @@ main(void)
 #endif

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_9beta02 Your_png_h_is_not_version_1_6_9beta02;
+typedef png_libpng_version_1_6_15 Your_png_h_is_not_version_1_6_15;
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,7 +1,7 @@

 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
 *
- * Last changed in libpng 1.6.9 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.15 [November 20, 2014]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -100,7 +100,7 @@ png_set_interlace_handling(png_structrp png_ptr)
 {
   png_debug(1, "in png_set_interlace handling");

-   if (png_ptr && png_ptr->interlaced)
+   if (png_ptr != 0 && png_ptr->interlaced != 0)
   {
      png_ptr->transformations |= PNG_INTERLACE;
      return (7);
@@ -127,7 +127,7 @@ png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
   /* In libpng 1.6 it is possible to determine whether this is a read or write
    * operation and therefore to do more checking here for a valid call.
    */
-   if (png_ptr->mode & PNG_IS_READ_STRUCT)
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
   {
 #     ifdef PNG_READ_FILLER_SUPPORTED
         /* On read png_set_filler is always valid, regardless of the base PNG
@@ -210,7 +210,7 @@ png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc)

   png_set_filler(png_ptr, filler, filler_loc);
   /* The above may fail to do anything. */
-   if (png_ptr->transformations & PNG_FILLER)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      png_ptr->transformations |= PNG_ADD_ALPHA;
 }

@@ -327,9 +327,16 @@ png_do_swap(png_row_infop row_info, png_bytep row)

      for (i = 0; i < istop; i++, rp += 2)
      {
+#ifdef PNG_BUILTIN_BSWAP16_SUPPORTED
+         /* Feature added to libpng-1.6.11 for testing purposes, not
+          * enabled by default.
+          */
+         *(png_uint_16*)rp = __builtin_bswap16(*(png_uint_16*)rp);
+#else
         png_byte t = *rp;
         *rp = *(rp + 1);
         *(rp + 1) = t;
+#endif
      }
   }
 }
@@ -471,7 +478,7 @@ png_do_packswap(png_row_infop row_info, png_bytep row)
         *rp = table[*rp];
   }
 }
-#endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */
+#endif /* PACKSWAP || WRITE_PACKSWAP */

 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
@@ -503,7 +510,7 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
   {
      if (row_info->bit_depth == 8)
      {
-         if (at_start) /* Skip initial filler */
+         if (at_start != 0) /* Skip initial filler */
            ++sp;
         else          /* Skip initial channel and, for sp, the filler */
            sp += 2, ++dp;
@@ -517,7 +524,7 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)

      else if (row_info->bit_depth == 16)
      {
-         if (at_start) /* Skip initial filler */
+         if (at_start != 0) /* Skip initial filler */
            sp += 2;
         else          /* Skip initial channel and, for sp, the filler */
            sp += 4, dp += 2;
@@ -543,7 +550,7 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
   {
      if (row_info->bit_depth == 8)
      {
-         if (at_start) /* Skip initial filler */
+         if (at_start != 0) /* Skip initial filler */
            ++sp;
         else          /* Skip initial channels and, for sp, the filler */
            sp += 4, dp += 3;
@@ -557,7 +564,7 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)

      else if (row_info->bit_depth == 16)
      {
-         if (at_start) /* Skip initial filler */
+         if (at_start != 0) /* Skip initial filler */
            sp += 2;
         else          /* Skip initial channels and, for sp, the filler */
            sp += 8, dp += 6;
@@ -598,7 +605,7 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
 {
   png_debug(1, "in png_do_bgr");

-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      png_uint_32 row_width = row_info->width;
      if (row_info->bit_depth == 8)
@@ -668,7 +675,7 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
 #endif
   }
 }
-#endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
+#endif /* READ_BGR || WRITE_BGR */

 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
    defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
@@ -771,7 +778,7 @@ png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
      }
   }
 }
-#endif /* PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED */
+#endif /* CHECK_FOR_INVALID_INDEX */

 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
@@ -821,7 +828,7 @@ png_get_user_transform_ptr(png_const_structrp png_ptr)
 png_uint_32 PNGAPI
 png_get_current_row_number(png_const_structrp png_ptr)
 {
-   /* See the comments in png.h - this is the sub-image row when reading and
+   /* See the comments in png.h - this is the sub-image row when reading an
    * interlaced image.
    */
   if (png_ptr != NULL)
@@ -837,7 +844,6 @@ png_get_current_pass_number(png_const_structrp png_ptr)
      return png_ptr->pass;
   return 8; /* invalid */
 }
-#endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */
-#endif /* PNG_READ_USER_TRANSFORM_SUPPORTED ||
-          PNG_WRITE_USER_TRANSFORM_SUPPORTED */
-#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
+#endif /* USER_TRANSFORM_INFO */
+#endif /* READ_USER_TRANSFORM || WRITE_USER_TRANSFORM */
+#endif /* READ || WRITE */
--- a/pngwio.c
+++ b/pngwio.c
@@ -1,7 +1,7 @@

 /* pngwio.c - functions for data output
 *
- * Last changed in libpng 1.6.9 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.15 [November 20, 2014]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -151,7 +151,7 @@ png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr,
 #  endif
 #else
   PNG_UNUSED(output_flush_fn)
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+#endif /* WRITE_FLUSH */

 #ifdef PNG_READ_SUPPORTED
   /* It is an error to read while writing a png file */
@@ -165,4 +165,4 @@ png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr,
   }
 #endif
 }
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,7 +1,7 @@

 /* pngwrite.c - general routines to write a PNG file
 *
- * Last changed in libpng 1.6.9 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.15 [November 20, 2014]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -24,7 +24,7 @@ static void
 write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
   unsigned int where)
 {
-   if (info_ptr->unknown_chunks_num)
+   if (info_ptr->unknown_chunks_num != 0)
   {
      png_const_unknown_chunkp up;

@@ -33,7 +33,7 @@ write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
      for (up = info_ptr->unknown_chunks;
           up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
           ++up)
-         if (up->location & where)
+         if ((up->location & where) != 0)
      {
         /* If per-chunk unknown chunk handling is enabled use it, otherwise
          * just write the chunks the application has set.
@@ -69,7 +69,7 @@ write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
      }
   }
 }
-#endif /* PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED */
+#endif /* WRITE_UNKNOWN_CHUNKS */

 /* Writes all the PNG information.  This is the suggested way to use the
 * library.  If you have a new chunk to add, make a function to write it,
@@ -88,14 +88,14 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
+   if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
   {
   /* Write PNG signature */
   png_write_sig(png_ptr);

 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) && \
-       (png_ptr->mng_features_permitted))
+   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
+       png_ptr->mng_features_permitted != 0)
   {
      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
      png_ptr->mng_features_permitted = 0;
@@ -129,9 +129,9 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
    */
 #ifdef PNG_GAMMA_SUPPORTED
 #  ifdef PNG_WRITE_gAMA_SUPPORTED
-      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
-         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) &&
-         (info_ptr->valid & PNG_INFO_gAMA))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
+          (info_ptr->valid & PNG_INFO_gAMA) != 0)
         png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
 #  endif
 #endif
@@ -141,11 +141,11 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
    * and it matches one of the known sRGB ones issue a warning.
    */
 #  ifdef PNG_WRITE_iCCP_SUPPORTED
-      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
-         (info_ptr->valid & PNG_INFO_iCCP))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->valid & PNG_INFO_iCCP) != 0)
      {
 #        ifdef PNG_WRITE_sRGB_SUPPORTED
-            if (info_ptr->valid & PNG_INFO_sRGB)
+            if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
               png_app_warning(png_ptr,
                  "profile matches sRGB but writing iCCP instead");
 #        endif
@@ -159,22 +159,22 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
 #  endif

 #  ifdef PNG_WRITE_sRGB_SUPPORTED
-      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
-         (info_ptr->valid & PNG_INFO_sRGB))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->valid & PNG_INFO_sRGB) != 0)
         png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
 #  endif /* WRITE_sRGB */
 #endif /* COLORSPACE */

 #ifdef PNG_WRITE_sBIT_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sBIT)
+   if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
      png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
 #endif

 #ifdef PNG_COLORSPACE_SUPPORTED
 #  ifdef PNG_WRITE_cHRM_SUPPORTED
-      if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
-         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) &&
-         (info_ptr->valid & PNG_INFO_cHRM))
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
+         (info_ptr->valid & PNG_INFO_cHRM) != 0)
         png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
 #  endif
 #endif
@@ -201,19 +201,19 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)

   png_write_info_before_PLTE(png_ptr, info_ptr);

-   if (info_ptr->valid & PNG_INFO_PLTE)
+   if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
      png_write_PLTE(png_ptr, info_ptr->palette,
          (png_uint_32)info_ptr->num_palette);

-   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   else if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) !=0)
      png_error(png_ptr, "Valid palette required for paletted images");

 #ifdef PNG_WRITE_tRNS_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_tRNS)
+   if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
   {
 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
      /* Invert the alpha channel (in tRNS) */
-      if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
+      if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
          info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
         int j;
@@ -227,42 +227,42 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
   }
 #endif
 #ifdef PNG_WRITE_bKGD_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_bKGD)
+   if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
      png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
 #endif

 #ifdef PNG_WRITE_hIST_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_hIST)
+   if ((info_ptr->valid & PNG_INFO_hIST) != 0)
      png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
 #endif

 #ifdef PNG_WRITE_oFFs_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_oFFs)
+   if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
      png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
          info_ptr->offset_unit_type);
 #endif

 #ifdef PNG_WRITE_pCAL_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_pCAL)
+   if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
      png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
          info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
          info_ptr->pcal_units, info_ptr->pcal_params);
 #endif

 #ifdef PNG_WRITE_sCAL_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sCAL)
+   if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
      png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
          info_ptr->scal_s_width, info_ptr->scal_s_height);
 #endif /* sCAL */

 #ifdef PNG_WRITE_pHYs_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_pHYs)
+   if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
      png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
          info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
 #endif /* pHYs */

 #ifdef PNG_WRITE_tIME_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_tIME)
+   if ((info_ptr->valid & PNG_INFO_tIME) != 0)
   {
      png_write_tIME(png_ptr, &(info_ptr->mod_time));
      png_ptr->mode |= PNG_WROTE_tIME;
@@ -270,7 +270,7 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
 #endif /* tIME */

 #ifdef PNG_WRITE_sPLT_SUPPORTED
-   if (info_ptr->valid & PNG_INFO_sPLT)
+   if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
      for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
         png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
 #endif /* sPLT */
@@ -292,11 +292,14 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
             info_ptr->text[i].lang,
             info_ptr->text[i].lang_key,
             info_ptr->text[i].text);
+         /* Mark this chunk as written */
+         if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+         else
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
-          png_warning(png_ptr, "Unable to write international text");
+         png_warning(png_ptr, "Unable to write international text");
 #endif
-          /* Mark this chunk as written */
-          info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
      }

      /* If we want a compressed text chunk */
@@ -305,13 +308,12 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
 #ifdef PNG_WRITE_zTXt_SUPPORTED
         /* Write compressed chunk */
         png_write_zTXt(png_ptr, info_ptr->text[i].key,
-             info_ptr->text[i].text, 0,
-             info_ptr->text[i].compression);
+             info_ptr->text[i].text, info_ptr->text[i].compression);
+         /* Mark this chunk as written */
+         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
         png_warning(png_ptr, "Unable to write compressed text");
 #endif
-         /* Mark this chunk as written */
-         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
      }

      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
@@ -349,7 +351,7 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
   if (png_ptr == NULL)
      return;

-   if (!(png_ptr->mode & PNG_HAVE_IDAT))
+   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
      png_error(png_ptr, "No IDATs written into file");

 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
@@ -365,8 +367,8 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
 #endif
 #ifdef PNG_WRITE_tIME_SUPPORTED
      /* Check to see if user has supplied a time chunk */
-      if ((info_ptr->valid & PNG_INFO_tIME) &&
-          !(png_ptr->mode & PNG_WROTE_tIME))
+      if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
+          (png_ptr->mode & PNG_WROTE_tIME) == 0)
         png_write_tIME(png_ptr, &(info_ptr->mod_time));

 #endif
@@ -387,11 +389,14 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
                info_ptr->text[i].lang,
                info_ptr->text[i].lang_key,
                info_ptr->text[i].text);
+            /* Mark this chunk as written */
+            if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+            else
+               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
            png_warning(png_ptr, "Unable to write international text");
 #endif
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
         }

         else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
@@ -399,13 +404,12 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
 #ifdef PNG_WRITE_zTXt_SUPPORTED
            /* Write compressed chunk */
            png_write_zTXt(png_ptr, info_ptr->text[i].key,
-                info_ptr->text[i].text, 0,
-                info_ptr->text[i].compression);
+                info_ptr->text[i].text, info_ptr->text[i].compression);
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
 #else
            png_warning(png_ptr, "Unable to write compressed text");
 #endif
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
         }

         else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
@@ -414,12 +418,11 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)
            /* Write uncompressed chunk */
            png_write_tEXt(png_ptr, info_ptr->text[i].key,
                info_ptr->text[i].text, 0);
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
 #else
            png_warning(png_ptr, "Unable to write uncompressed text");
 #endif
-
-            /* Mark this chunk as written */
-            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
         }
      }
 #endif
@@ -432,6 +435,7 @@ png_write_end(png_structrp png_ptr, png_inforp info_ptr)

   /* Write end of PNG file */
   png_write_IEND(png_ptr);
+
   /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
    * and restored again in libpng-1.2.30, may cause some applications that
    * do not set png_ptr->output_flush_fn to crash.  If your application
@@ -479,7 +483,7 @@ png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
 {
 #ifndef PNG_USER_MEM_SUPPORTED
   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
-      error_fn, warn_fn, NULL, NULL, NULL);
+       error_fn, warn_fn, NULL, NULL, NULL);
 #else
   return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
       warn_fn, NULL, NULL, NULL);
@@ -492,8 +496,8 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
 {
   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
-      error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
-#endif /* PNG_USER_MEM_SUPPORTED */
+       error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
+#endif /* USER_MEM */
   if (png_ptr != NULL)
   {
      /* Set the zlib control values to defaults; they can be overridden by the
@@ -517,7 +521,7 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
      png_ptr->zlib_text_mem_level = 8;
      png_ptr->zlib_text_window_bits = 15;
      png_ptr->zlib_text_method = 8;
-#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
+#endif /* WRITE_COMPRESSED_TEXT */

      /* This is a highly dubious configuration option; by default it is off,
       * but it may be appropriate for private builds that are testing
@@ -525,10 +529,10 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
       * applications that must not fail to write at all costs!
       */
 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
-      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
      /* In stable builds only warn if an application error can be completely
       * handled.
       */
+      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
 #endif

      /* App warnings are warnings in release (or release candidate) builds but
@@ -614,7 +618,7 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
 {
   png_debug(1, "in png_do_write_intrapixel");

-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      int bytes_per_pixel;
      png_uint_32 row_width = row_info->width;
@@ -667,10 +671,10 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
            *(rp + 5) = (png_byte)(blue & 0xff);
         }
      }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
   }
 }
-#endif /* PNG_MNG_FEATURES_SUPPORTED */
+#endif /* MNG_FEATURES */

 /* Called by user to write a row of image data */
 void PNGAPI
@@ -689,44 +693,44 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
   {
      /* Make sure we wrote the header info */
-      if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
+      if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
         png_error(png_ptr,
             "png_write_info was never called before png_write_row");

      /* Check for transforms that have been set but were defined out */
 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
-      if (png_ptr->transformations & PNG_INVERT_MONO)
+      if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
         png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
-      if (png_ptr->transformations & PNG_FILLER)
+      if ((png_ptr->transformations & PNG_FILLER) != 0)
         png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
 #endif
 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
    defined(PNG_READ_PACKSWAP_SUPPORTED)
-      if (png_ptr->transformations & PNG_PACKSWAP)
+      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
         png_warning(png_ptr,
             "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
-      if (png_ptr->transformations & PNG_PACK)
+      if ((png_ptr->transformations & PNG_PACK) != 0)
         png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
-      if (png_ptr->transformations & PNG_SHIFT)
+      if ((png_ptr->transformations & PNG_SHIFT) != 0)
         png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
-      if (png_ptr->transformations & PNG_BGR)
+      if ((png_ptr->transformations & PNG_BGR) != 0)
         png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
 #endif

 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
-      if (png_ptr->transformations & PNG_SWAP_BYTES)
+      if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
         png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
 #endif

@@ -735,12 +739,13 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* If interlaced and not interested in row, return */
-   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      switch (png_ptr->pass)
      {
         case 0:
-            if (png_ptr->row_number & 0x07)
+            if ((png_ptr->row_number & 0x07) != 0)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -748,7 +753,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 1:
-            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
+            if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -764,7 +769,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 3:
-            if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)
+            if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -780,7 +785,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 5:
-            if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)
+            if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -788,7 +793,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
            break;

         case 6:
-            if (!(png_ptr->row_number & 0x01))
+            if ((png_ptr->row_number & 0x01) == 0)
            {
               png_write_finish_row(png_ptr);
               return;
@@ -822,11 +827,11 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* Handle interlacing */
   if (png_ptr->interlaced && png_ptr->pass < 6 &&
-       (png_ptr->transformations & PNG_INTERLACE))
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
   {
      png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
      /* This should always get caught above, but still ... */
-      if (!(row_info.width))
+      if (row_info.width == 0)
      {
         png_write_finish_row(png_ptr);
         return;
@@ -836,7 +841,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)

 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
   /* Handle other transformations */
-   if (png_ptr->transformations)
+   if (png_ptr->transformations != 0)
      png_do_write_transformations(png_ptr, &row_info);
 #endif

@@ -857,7 +862,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
    * 4. The filter_method is 64 and
    * 5. The color_type is RGB or RGBA
    */
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
   {
      /* Intrapixel differencing */
@@ -910,7 +915,7 @@ png_write_flush(png_structrp png_ptr)
   png_ptr->flush_rows = 0;
   png_flush(png_ptr);
 }
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+#endif /* WRITE_FLUSH */

 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
 static void png_reset_filter_heuristics(png_structrp png_ptr);/* forward decl */
@@ -923,18 +928,24 @@ png_write_destroy(png_structrp png_ptr)
   png_debug(1, "in png_write_destroy");

   /* Free any memory zlib uses */
-   if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
+   if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
      deflateEnd(&png_ptr->zstream);

   /* Free our memory.  png_free checks NULL for us. */
   png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
   png_free(png_ptr, png_ptr->row_buf);
+   png_ptr->row_buf = NULL;
 #ifdef PNG_WRITE_FILTER_SUPPORTED
   png_free(png_ptr, png_ptr->prev_row);
   png_free(png_ptr, png_ptr->sub_row);
   png_free(png_ptr, png_ptr->up_row);
   png_free(png_ptr, png_ptr->avg_row);
   png_free(png_ptr, png_ptr->paeth_row);
+   png_ptr->prev_row = NULL;
+   png_ptr->sub_row = NULL;
+   png_ptr->up_row = NULL;
+   png_ptr->avg_row = NULL;
+   png_ptr->paeth_row = NULL;
 #endif

 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
@@ -942,10 +953,13 @@ png_write_destroy(png_structrp png_ptr)
   png_reset_filter_heuristics(png_ptr);
   png_free(png_ptr, png_ptr->filter_costs);
   png_free(png_ptr, png_ptr->inv_filter_costs);
+   png_ptr->filter_costs = NULL;
+   png_ptr->inv_filter_costs = NULL;
 #endif

 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
   png_free(png_ptr, png_ptr->chunk_list);
+   png_ptr->chunk_list = NULL;
 #endif

   /* The error handling and memory handling information is left intact at this
@@ -991,7 +1005,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
      return;

 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
       (method == PNG_INTRAPIXEL_DIFFERENCING))
      method = PNG_FILTER_TYPE_BASE;

@@ -1005,7 +1019,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
         case 6:
         case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
            /* FALL THROUGH */
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */
         case PNG_FILTER_VALUE_NONE:
            png_ptr->do_filter = PNG_FILTER_NONE; break;

@@ -1027,7 +1041,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
 #else
         default:
            png_app_error(png_ptr, "Unknown row filter for method 0");
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */
      }

      /* If we have allocated the row_buf, this means we have already started
@@ -1042,14 +1056,16 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
      if (png_ptr->row_buf != NULL)
      {
 #ifdef PNG_WRITE_FILTER_SUPPORTED
-         if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
+         if ((png_ptr->do_filter & PNG_FILTER_SUB) != 0 &&
+             png_ptr->sub_row == NULL)
         {
            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
                (png_ptr->rowbytes + 1));
            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
         }

-         if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
+         if ((png_ptr->do_filter & PNG_FILTER_UP) != 0 &&
+              png_ptr->up_row == NULL)
         {
            if (png_ptr->prev_row == NULL)
            {
@@ -1066,7 +1082,8 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            }
         }

-         if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
+         if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0 &&
+              png_ptr->avg_row == NULL)
         {
            if (png_ptr->prev_row == NULL)
            {
@@ -1083,7 +1100,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
            }
         }

-         if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
+         if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0 &&
             png_ptr->paeth_row == NULL)
         {
            if (png_ptr->prev_row == NULL)
@@ -1101,7 +1118,7 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
         }

         if (png_ptr->do_filter == PNG_NO_FILTERS)
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */
            png_ptr->do_filter = PNG_FILTER_NONE;
      }
   }
@@ -1244,7 +1261,7 @@ png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
   /* The internal API allocates all the arrays and ensures that the elements of
    * those arrays are set to the default value.
    */
-   if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
+   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
      return;

   /* If using the weighted method copy in the weights. */
@@ -1299,7 +1316,7 @@ png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
   /* The internal API allocates all the arrays and ensures that the elements of
    * those arrays are set to the default value.
    */
-   if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
+   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
      return;

   /* If using the weighted method copy in the weights. */
@@ -1353,7 +1370,7 @@ png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
   }
 }
 #endif /* FIXED_POINT */
-#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
+#endif /* WRITE_WEIGHTED_FILTER */

 void PNGAPI
 png_set_compression_level(png_structrp png_ptr, int level)
@@ -1510,7 +1527,7 @@ png_set_text_compression_method(png_structrp png_ptr, int method)

   png_ptr->zlib_text_method = method;
 }
-#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
 /* end of API added to libpng-1.5.4 */

 void PNGAPI
@@ -1546,81 +1563,117 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
   if (png_ptr == NULL || info_ptr == NULL)
      return;

+   if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
+   {
+      png_app_error(png_ptr, "no rows for png_write_image to write");
+      return;
+   }
+
   /* Write the file header information. */
   png_write_info(png_ptr, info_ptr);

   /* ------ these transformations don't touch the info structure ------- */

-#ifdef PNG_WRITE_INVERT_SUPPORTED
   /* Invert monochrome pixels */
-   if (transforms & PNG_TRANSFORM_INVERT_MONO)
+   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
+#ifdef PNG_WRITE_INVERT_SUPPORTED
      png_set_invert_mono(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
 #endif

-#ifdef PNG_WRITE_SHIFT_SUPPORTED
   /* Shift the pixels up to a legal bit depth and fill in
    * as appropriate to correctly scale the image.
    */
-   if ((transforms & PNG_TRANSFORM_SHIFT)
-       && (info_ptr->valid & PNG_INFO_sBIT))
-      png_set_shift(png_ptr, &info_ptr->sig_bit);
+   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+         png_set_shift(png_ptr, &info_ptr->sig_bit);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
 #endif

-#ifdef PNG_WRITE_PACK_SUPPORTED
   /* Pack pixels into bytes */
-   if (transforms & PNG_TRANSFORM_PACKING)
-       png_set_packing(png_ptr);
+   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
+#ifdef PNG_WRITE_PACK_SUPPORTED
+      png_set_packing(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
 #endif

-#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
   /* Swap location of alpha bytes from ARGB to RGBA */
-   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
+   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
      png_set_swap_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
 #endif

+   /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
+    * RGB, note that the code expects the input color type to be G or RGB; no
+    * alpha channel.
+    */
+   if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
+      PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
+   {
 #ifdef PNG_WRITE_FILLER_SUPPORTED
-   /* Pack XRGB/RGBX/ARGB/RGBA into RGB (4 channels -> 3 channels) */
-   if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
-      png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
+      if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
+      {
+         if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+            png_app_error(png_ptr,
+               "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");

-   else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
-      png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+         /* Continue if ignored - this is the pre-1.6.10 behavior */
+         png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
+      }
+
+      else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+         png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
 #endif
+   }

-#ifdef PNG_WRITE_BGR_SUPPORTED
   /* Flip BGR pixels to RGB */
-   if (transforms & PNG_TRANSFORM_BGR)
+   if ((transforms & PNG_TRANSFORM_BGR) != 0)
+#ifdef PNG_WRITE_BGR_SUPPORTED
      png_set_bgr(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
 #endif

-#ifdef PNG_WRITE_SWAP_SUPPORTED
   /* Swap bytes of 16-bit files to most significant byte first */
-   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
+   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
+#ifdef PNG_WRITE_SWAP_SUPPORTED
      png_set_swap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
 #endif

-#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
   /* Swap bits of 1, 2, 4 bit packed pixel formats */
-   if (transforms & PNG_TRANSFORM_PACKSWAP)
+   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
      png_set_packswap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
 #endif

-#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
   /* Invert the alpha channel from opacity to transparency */
-   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
+   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
      png_set_invert_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
 #endif

   /* ----------------------- end of transformations ------------------- */

   /* Write the bits */
-   if (info_ptr->valid & PNG_INFO_IDAT)
-       png_write_image(png_ptr, info_ptr->row_pointers);
+   png_write_image(png_ptr, info_ptr->row_pointers);

   /* It is REQUIRED to call this to finish writing the rest of the file */
   png_write_end(png_ptr, info_ptr);

-   PNG_UNUSED(transforms)   /* Quiet compiler warnings */
   PNG_UNUSED(params)
 }
 #endif
@@ -1697,14 +1750,14 @@ png_write_image_16bit(png_voidp argument)
      display->first_row);
   png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
   png_uint_16p row_end;
-   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
+   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
   int aindex = 0;
   png_uint_32 y = image->height;

-   if (image->format & PNG_FORMAT_FLAG_ALPHA)
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
   {
 #     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if (image->format & PNG_FORMAT_FLAG_AFIRST)
+         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
         {
            aindex = -1;
            ++input_row; /* To point to the first component */
@@ -1854,15 +1907,15 @@ png_write_image_8bit(png_voidp argument)
      display->first_row);
   png_bytep output_row = png_voidcast(png_bytep, display->local_row);
   png_uint_32 y = image->height;
-   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
+   const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;

-   if (image->format & PNG_FORMAT_FLAG_ALPHA)
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
   {
      png_bytep row_end;
      int aindex;

 #     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if (image->format & PNG_FORMAT_FLAG_AFIRST)
+         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
         {
            aindex = -1;
            ++input_row; /* To point to the first component */
@@ -1959,7 +2012,7 @@ png_image_set_PLTE(png_image_write_control *display)
 #  endif

 #  ifdef PNG_FORMAT_BGR_SUPPORTED
-      const int bgr = (format & PNG_FORMAT_FLAG_BGR) ? 2 : 0;
+      const int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
 #  else
 #     define bgr 0
 #  endif
@@ -1976,13 +2029,13 @@ png_image_set_PLTE(png_image_write_control *display)
      /* This gets automatically converted to sRGB with reversal of the
       * pre-multiplication if the color-map has an alpha channel.
       */
-      if (format & PNG_FORMAT_FLAG_LINEAR)
+      if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
      {
         png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);

         entry += i * channels;

-         if (channels & 1) /* no alpha */
+         if ((channels & 1) != 0) /* no alpha */
         {
            if (channels >= 3) /* RGB */
            {
@@ -2094,10 +2147,11 @@ png_image_write_main(png_voidp argument)
   png_inforp info_ptr = image->opaque->info_ptr;
   png_uint_32 format = image->format;

-   int colormap = (format & PNG_FORMAT_FLAG_COLORMAP) != 0;
-   int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR) != 0; /* input */
-   int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0;
-   int write_16bit = linear && !colormap && !display->convert_to_8bit;
+   /* The following four ints are actually booleans */
+   int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
+   int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
+   int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
+   int write_16bit = linear && !colormap && (display->convert_to_8bit == 0);

 #  ifdef PNG_BENIGN_ERRORS_SUPPORTED
      /* Make sure we error out on any bad situation */
@@ -2109,7 +2163,7 @@ png_image_write_main(png_voidp argument)
      display->row_stride = PNG_IMAGE_ROW_STRIDE(*image);

   /* Set the required transforms then write the rows in the correct order. */
-   if (format & PNG_FORMAT_FLAG_COLORMAP)
+   if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
   {
      if (display->colormap != NULL && image->colormap_entries > 0)
      {
@@ -2141,12 +2195,12 @@ png_image_write_main(png_voidp argument)
    * write an interlaced image.
    */

-   if (write_16bit)
+   if (write_16bit != 0)
   {
      /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
      png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);

-      if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB))
+      if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
         png_set_cHRM_fixed(png_ptr, info_ptr,
            /* color      x       y */
            /* white */ 31270, 32900,
@@ -2156,7 +2210,7 @@ png_image_write_main(png_voidp argument)
         );
   }

-   else if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB))
+   else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
      png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);

   /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
@@ -2173,27 +2227,27 @@ png_image_write_main(png_voidp argument)
    *
    * First check for a little endian system if writing 16 bit files.
    */
-   if (write_16bit)
+   if (write_16bit != 0)
   {
      PNG_CONST png_uint_16 le = 0x0001;

-      if (*(png_const_bytep)&le)
+      if ((*(png_const_bytep) & le) != 0)
         png_set_swap(png_ptr);
   }

 #  ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
-      if (format & PNG_FORMAT_FLAG_BGR)
+      if ((format & PNG_FORMAT_FLAG_BGR) != 0)
      {
-         if (!colormap && (format & PNG_FORMAT_FLAG_COLOR) != 0)
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
            png_set_bgr(png_ptr);
         format &= ~PNG_FORMAT_FLAG_BGR;
      }
 #  endif

 #  ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-      if (format & PNG_FORMAT_FLAG_AFIRST)
+      if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
      {
-         if (!colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
            png_set_swap_alpha(png_ptr);
         format &= ~PNG_FORMAT_FLAG_AFIRST;
      }
@@ -2202,7 +2256,7 @@ png_image_write_main(png_voidp argument)
   /* If there are 16 or fewer color-map entries we wrote a lower bit depth
    * above, but the application data is still byte packed.
    */
-   if (colormap && image->colormap_entries <= 16)
+   if (colormap != 0 && image->colormap_entries <= 16)
      png_set_packing(png_ptr);

   /* That should have handled all (both) the transforms. */
@@ -2214,7 +2268,7 @@ png_image_write_main(png_voidp argument)
      png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
      ptrdiff_t row_bytes = display->row_stride;

-      if (linear)
+      if (linear != 0)
         row_bytes *= (sizeof (png_uint_16));

      if (row_bytes < 0)
@@ -2240,14 +2294,15 @@ png_image_write_main(png_voidp argument)
    * before it is written.  This only applies when the input is 16-bit and
    * either there is an alpha channel or it is converted to 8-bit.
    */
-   if ((linear && alpha) || (!colormap && display->convert_to_8bit))
+   if ((linear != 0 && alpha != 0 ) ||
+       (colormap == 0 && display->convert_to_8bit != 0))
   {
      png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
         png_get_rowbytes(png_ptr, info_ptr)));
      int result;

      display->local_row = row;
-      if (write_16bit)
+      if (write_16bit != 0)
         result = png_safe_execute(image, png_write_image_16bit, display);
      else
         result = png_safe_execute(image, png_write_image_8bit, display);
@@ -2256,7 +2311,7 @@ png_image_write_main(png_voidp argument)
      png_free(png_ptr, row);

      /* Skip the 'write_end' on error: */
-      if (!result)
+      if (result == 0)
         return 0;
   }

@@ -2289,7 +2344,7 @@ png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
   {
      if (file != NULL)
      {
-         if (png_image_write_init(image))
+         if (png_image_write_init(image) != 0)
         {
            png_image_write_control display;
            int result;
@@ -2344,7 +2399,7 @@ png_image_write_to_file(png_imagep image, const char *file_name,
         if (fp != NULL)
         {
            if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
-               row_stride, colormap))
+               row_stride, colormap) != 0)
            {
               int error; /* from fflush/fclose */

@@ -2395,6 +2450,6 @@ png_image_write_to_file(png_imagep image, const char *file_name,
   else
      return 0;
 }
-#endif /* PNG_STDIO_SUPPORTED */
+#endif /* STDIO */
 #endif /* SIMPLIFIED_WRITE */
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -1,7 +1,7 @@

 /* pngwtran.c - transforms the data in a row for PNG writers
 *
- * Last changed in libpng 1.6.9 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.15 [November 20, 2014]
 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -177,7 +177,7 @@ png_do_shift(png_row_infop row_info, png_bytep row,
      int shift_start[4], shift_dec[4];
      int channels = 0;

-      if (row_info->color_type & PNG_COLOR_MASK_COLOR)
+      if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
      {
         shift_start[channels] = row_info->bit_depth - bit_depth->red;
         shift_dec[channels] = bit_depth->red;
@@ -199,7 +199,7 @@ png_do_shift(png_row_infop row_info, png_bytep row,
         channels++;
      }

-      if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+      if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
      {
         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
         shift_dec[channels] = bit_depth->alpha;
@@ -353,7 +353,7 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = save[1];
            }
         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
      }

      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
@@ -392,7 +392,7 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = save[1];
            }
         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
      }
   }
 }
@@ -449,7 +449,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = (png_byte)(255 - *(sp++));
            }
         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
      }

      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
@@ -487,7 +487,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
               *(dp++) = (png_byte)(255 - *(sp++));
            }
         }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
+#endif /* WRITE_16BIT */
      }
   }
 }
@@ -505,7 +505,7 @@ png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
      return;

 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
      if (png_ptr->write_user_transform_fn != NULL)
         (*(png_ptr->write_user_transform_fn)) /* User write transform
                                                 function */
@@ -521,52 +521,54 @@ png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
 #endif

 #ifdef PNG_WRITE_FILLER_SUPPORTED
-   if (png_ptr->transformations & PNG_FILLER)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
         !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
 #endif

 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_PACKSWAP)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
      png_do_packswap(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
      png_do_pack(row_info, png_ptr->row_buf + 1,
          (png_uint_32)png_ptr->bit_depth);
 #endif

 #ifdef PNG_WRITE_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
+#  ifdef PNG_16BIT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
      png_do_swap(row_info, png_ptr->row_buf + 1);
+#  endif
 #endif

 #ifdef PNG_WRITE_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
      png_do_shift(row_info, png_ptr->row_buf + 1,
          &(png_ptr->shift));
 #endif

 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_ALPHA)
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
      png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
      png_do_bgr(row_info, png_ptr->row_buf + 1);
 #endif

 #ifdef PNG_WRITE_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
      png_do_invert(row_info, png_ptr->row_buf + 1);
 #endif
 }
-#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE_TRANSFORMS */
+#endif /* WRITE */
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,8 +1,8 @@

 /* pngwutil.c - utilities to write a PNG file
 *
- * Last changed in libpng 1.6.2 [April 25, 2013]
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
@@ -136,7 +136,7 @@ png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,
      png_write_data(png_ptr, data, length);

      /* Update the CRC after writing the data,
-       * in case that the user I/O routine alters it.
+       * in case the user I/O routine alters it.
       */
      png_calculate_crc(png_ptr, data, length);
   }
@@ -181,7 +181,7 @@ png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,

   /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
   if (length > PNG_UINT_31_MAX)
-      png_error(png_ptr, "length exceeds PNG maxima");
+      png_error(png_ptr, "length exceeds PNG maximum");

   png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
   png_write_chunk_data(png_ptr, data, length);
@@ -204,14 +204,14 @@ png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
 static png_alloc_size_t
 png_image_size(png_structrp png_ptr)
 {
-   /* Only return sizes up to the maximum of a png_uint_32, do this by limiting
+   /* Only return sizes up to the maximum of a png_uint_32; do this by limiting
    * the width and height used to 15 bits.
    */
   png_uint_32 h = png_ptr->height;

   if (png_ptr->rowbytes < 32768 && h < 32768)
   {
-      if (png_ptr->interlaced)
+      if (png_ptr->interlaced != 0)
      {
         /* Interlacing makes the image larger because of the replication of
          * both the filter byte and the padding to a byte boundary.
@@ -286,9 +286,7 @@ optimize_cmf(png_bytep data, png_alloc_size_t data_size)
      }
   }
 }
-#else
-#  define optimize_cmf(dp,dl) ((void)0)
-#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
+#endif /* WRITE_OPTIMIZE_CMF */

 /* Initialize the compressor for the appropriate type of compression. */
 static int
@@ -297,6 +295,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
 {
   if (png_ptr->zowner != 0)
   {
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
      char msg[64];

      PNG_STRING_FROM_CHUNK(msg, owner);
@@ -308,7 +307,8 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
       * are minimal.
       */
      (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
-#     if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+#endif
+#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
         png_warning(png_ptr, msg);

         /* Attempt sane error recovery */
@@ -319,9 +319,9 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
         }

         png_ptr->zowner = 0;
-#     else
+#else
         png_error(png_ptr, msg);
-#     endif
+#endif
   }

   {
@@ -334,7 +334,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,

      if (owner == png_IDAT)
      {
-         if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)
+         if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
            strategy = png_ptr->zlib_strategy;

         else if (png_ptr->do_filter != PNG_FILTER_NONE)
@@ -346,20 +346,20 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,

      else
      {
-#        ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
            level = png_ptr->zlib_text_level;
            method = png_ptr->zlib_text_method;
            windowBits = png_ptr->zlib_text_window_bits;
            memLevel = png_ptr->zlib_text_mem_level;
            strategy = png_ptr->zlib_text_strategy;
-#        else
+#else
            /* If customization is not supported the values all come from the
             * IDAT values except for the strategy, which is fixed to the
             * default.  (This is the pre-1.6.0 behavior too, although it was
             * implemented in a very different way.)
             */
            strategy = Z_DEFAULT_STRATEGY;
-#        endif
+#endif
      }

      /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
@@ -386,7 +386,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
      }

      /* Check against the previous initialized values, if any. */
-      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) &&
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
         (png_ptr->zlib_set_level != level ||
         png_ptr->zlib_set_method != method ||
         png_ptr->zlib_set_window_bits != windowBits ||
@@ -410,7 +410,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
      /* Now initialize if required, setting the new parameters, otherwise just
       * to a simple reset to the previous parameters.
       */
-      if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
         ret = deflateReset(&png_ptr->zstream);

      else
@@ -492,7 +492,7 @@ png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
   int ret;

   /* To find the length of the output it is necessary to first compress the
-    * input, the result is buffered rather than using the two-pass algorithm
+    * input. The result is buffered rather than using the two-pass algorithm
    * that is used on the inflate side; deflate is assumed to be slower and a
    * PNG writer is assumed to have more memory available than a PNG reader.
    *
@@ -589,7 +589,7 @@ png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
      }
      while (ret == Z_OK);

-      /* There may be some space left in the last output buffer, this needs to
+      /* There may be some space left in the last output buffer. This needs to
       * be subtracted from output_len.
       */
      output_len -= png_ptr->zstream.avail_out;
@@ -612,14 +612,15 @@ png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
      /* Reset zlib for another zTXt/iTXt or image data */
      png_ptr->zowner = 0;

-      /* The only success case is Z_STREAM_END, input_len must be 0, if not this
+      /* The only success case is Z_STREAM_END, input_len must be 0; if not this
       * is an internal error.
       */
      if (ret == Z_STREAM_END && input_len == 0)
      {
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
         /* Fix up the deflate header, if required */
         optimize_cmf(comp->output, comp->input_len);
-
+#endif
         /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
          * function above to return Z_STREAM_END on an error (though it never
          * does in the current versions of zlib.)
@@ -662,7 +663,7 @@ png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
   if (output_len > 0)
      png_error(png_ptr, "error writing ancillary chunked compressed data");
 }
-#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
+#endif /* WRITE_COMPRESSED_TEXT */

 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
@@ -699,7 +700,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
      if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
         *new_key++ = ch, ++key_len, space = 0;

-      else if (!space)
+      else if (space == 0)
      {
         /* A space or an invalid character when one wasn't seen immediately
          * before; output just a space.
@@ -711,14 +712,14 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
            bad_character = ch;
      }

-      else if (!bad_character)
+      else if (bad_character == 0)
         bad_character = ch; /* just skip it, record the first error */
   }

-   if (key_len > 0 && space) /* trailing space */
+   if (key_len > 0 && space != 0) /* trailing space */
   {
      --key_len, --new_key;
-      if (!bad_character)
+      if (bad_character == 0)
         bad_character = 32;
   }

@@ -728,11 +729,12 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
   if (key_len == 0)
      return 0;

+#ifdef PNG_WARNINGS_SUPPORTED
   /* Try to only output one warning per keyword: */
-   if (*key) /* keyword too long */
+   if (*key != 0) /* keyword too long */
      png_warning(png_ptr, "keyword truncated");

-   else if (bad_character)
+   else if (bad_character != 0)
   {
      PNG_WARNING_PARAMETERS(p)

@@ -741,10 +743,11 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)

      png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
   }
+#endif /* WARNINGS */

   return key_len;
 }
-#endif
+#endif /* WRITE_TEXT || WRITE_pCAL || WRITE_iCCP || WRITE_sPLT */

 /* Write the IHDR chunk, and update the png_struct with the necessary
 * information.  Note that the rest of this code depends upon this
@@ -845,8 +848,8 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
    */
   if (
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
-       ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
       (color_type == PNG_COLOR_TYPE_RGB ||
        color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
       (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
@@ -898,7 +901,7 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
   /* Write the chunk */
   png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);

-   if (!(png_ptr->do_filter))
+   if ((png_ptr->do_filter) == PNG_NO_FILTERS)
   {
      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
          png_ptr->bit_depth < 8)
@@ -927,7 +930,7 @@ png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,

   if ((
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-       !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
+       (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
 #endif
       num_pal == 0) || num_pal > 256)
   {
@@ -943,7 +946,7 @@ png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
      }
   }

-   if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
   {
      png_warning(png_ptr,
          "Ignoring request to write a PLTE chunk in grayscale PNG");
@@ -998,7 +1001,7 @@ png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
 * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
 *
 * The routine manages the acquire and release of the png_ptr->zstream by
- * checking and (at the end) clearing png_ptr->zowner, it does some sanity
+ * checking and (at the end) clearing png_ptr->zowner; it does some sanity
 * checks on the 'mode' flags while doing this.
 */
 void /* PRIVATE */
@@ -1058,7 +1061,7 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
      input_len += png_ptr->zstream.avail_in;
      png_ptr->zstream.avail_in = 0;

-      /* OUTPUT: write complete IDAT chunks when avail_out drops to zero, note
+      /* OUTPUT: write complete IDAT chunks when avail_out drops to zero. Note
       * that these two zstream fields are preserved across the calls, therefore
       * there is no need to set these up on entry to the loop.
       */
@@ -1070,11 +1073,11 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
         /* Write an IDAT containing the data then reset the buffer.  The
          * first IDAT may need deflate header optimization.
          */
-#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
-               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+            if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+                png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
               optimize_cmf(data, png_image_size(png_ptr));
-#        endif
+#endif

         png_write_complete_chunk(png_ptr, png_IDAT, data, size);
         png_ptr->mode |= PNG_HAVE_IDAT;
@@ -1090,7 +1093,7 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
            continue;
      }

-      /* The order of these checks doesn't matter much; it just effect which
+      /* The order of these checks doesn't matter much; it just affects which
       * possible error might be detected if multiple things go wrong at once.
       */
      if (ret == Z_OK) /* most likely return code! */
@@ -1116,11 +1119,11 @@ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
         png_bytep data = png_ptr->zbuffer_list->output;
         uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;

-#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
-            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
-               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
-               optimize_cmf(data, png_image_size(png_ptr));
-#        endif
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+         if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+             png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+            optimize_cmf(data, png_image_size(png_ptr));
+#endif

         png_write_complete_chunk(png_ptr, png_IDAT, data, size);
         png_ptr->zstream.avail_out = 0;
@@ -1193,6 +1196,7 @@ png_write_iCCP(png_structrp png_ptr, png_const_charp name,
   png_uint_32 profile_len;
   png_byte new_name[81]; /* 1 byte for the compression byte */
   compression_state comp;
+   png_uint_32 temp;

   png_debug(1, "in png_write_iCCP");

@@ -1207,7 +1211,8 @@ png_write_iCCP(png_structrp png_ptr, png_const_charp name,
   if (profile_len < 132)
      png_error(png_ptr, "ICC profile too short");

-   if (profile_len & 0x03)
+   temp = (png_uint_32) (*(profile+8));
+   if (temp > 3 && (profile_len & 0x03))
      png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");

   {
@@ -1339,7 +1344,7 @@ png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
   png_debug(1, "in png_write_sBIT");

   /* Make sure we don't depend upon the order of PNG_COLOR_8 */
-   if (color_type & PNG_COLOR_MASK_COLOR)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      png_byte maxbits;

@@ -1372,7 +1377,7 @@ png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
      size = 1;
   }

-   if (color_type & PNG_COLOR_MASK_ALPHA)
+   if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
   {
      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
      {
@@ -1459,9 +1464,9 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
      png_save_uint_16(buf + 2, tran->green);
      png_save_uint_16(buf + 4, tran->blue);
 #ifdef PNG_WRITE_16BIT_SUPPORTED
-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
 #else
-      if (buf[0] | buf[2] | buf[4])
+      if ((buf[0] | buf[2] | buf[4]) != 0)
 #endif
      {
         png_app_warning(png_ptr,
@@ -1492,8 +1497,8 @@ png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
   {
      if (
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-          (png_ptr->num_palette ||
-          (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
+          (png_ptr->num_palette != 0 ||
+          (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
 #endif
         back->index >= png_ptr->num_palette)
      {
@@ -1505,15 +1510,15 @@ png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
   }

-   else if (color_type & PNG_COLOR_MASK_COLOR)
+   else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      png_save_uint_16(buf, back->red);
      png_save_uint_16(buf + 2, back->green);
      png_save_uint_16(buf + 4, back->blue);
 #ifdef PNG_WRITE_16BIT_SUPPORTED
-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
 #else
-      if (buf[0] | buf[2] | buf[4])
+      if ((buf[0] | buf[2] | buf[4]) != 0)
 #endif
      {
         png_warning(png_ptr,
@@ -1608,7 +1613,7 @@ png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
    */
   png_write_chunk_data(png_ptr, new_key, key_len + 1);

-   if (text_len)
+   if (text_len != 0)
      png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);

   png_write_chunk_end(png_ptr);
@@ -1619,14 +1624,13 @@ png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
 /* Write a compressed text chunk */
 void /* PRIVATE */
 png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
-    png_size_t text_len, int compression)
+    int compression)
 {
   png_uint_32 key_len;
   png_byte new_key[81];
   compression_state comp;

   png_debug(1, "in png_write_zTXt");
-   PNG_UNUSED(text_len) /* Always use strlen */

   if (compression == PNG_TEXT_COMPRESSION_NONE)
   {
@@ -1734,7 +1738,7 @@ png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,

   png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));

-   if (compression)
+   if (compression != 0)
   {
      if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)
         png_error(png_ptr, png_ptr->zstream.msg);
@@ -1757,7 +1761,7 @@ png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,

   png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);

-   if (compression)
+   if (compression != 0)
      png_write_compressed_data_out(png_ptr, &comp);

   else
@@ -1981,12 +1985,13 @@ png_write_start_row(png_structrp png_ptr)
   }

   /* We only need to keep the previous row if we are using one of these. */
-   if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
+   if ((png_ptr->do_filter &
+      (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
   {
      /* Set up previous row buffer */
      png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);

-      if (png_ptr->do_filter & PNG_FILTER_UP)
+      if ((png_ptr->do_filter & PNG_FILTER_UP) != 0)
      {
         png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
            png_ptr->rowbytes + 1);
@@ -1994,7 +1999,7 @@ png_write_start_row(png_structrp png_ptr)
         png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
      }

-      if (png_ptr->do_filter & PNG_FILTER_AVG)
+      if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0)
      {
         png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
             png_ptr->rowbytes + 1);
@@ -2002,7 +2007,7 @@ png_write_start_row(png_structrp png_ptr)
         png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
      }

-      if (png_ptr->do_filter & PNG_FILTER_PAETH)
+      if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0)
      {
         png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
             png_ptr->rowbytes + 1);
@@ -2010,13 +2015,13 @@ png_write_start_row(png_structrp png_ptr)
         png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
      }
   }
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* If interlaced, we need to set up width and height of pass */
-   if (png_ptr->interlaced)
+   if (png_ptr->interlaced != 0)
   {
-      if (!(png_ptr->transformations & PNG_INTERLACE))
+      if ((png_ptr->transformations & PNG_INTERLACE) == 0)
      {
         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
             png_pass_ystart[0]) / png_pass_yinc[0];
@@ -2071,10 +2076,10 @@ png_write_finish_row(png_structrp png_ptr)

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   /* If interlaced, go to next pass */
-   if (png_ptr->interlaced)
+   if (png_ptr->interlaced != 0)
   {
      png_ptr->row_number = 0;
-      if (png_ptr->transformations & PNG_INTERLACE)
+      if ((png_ptr->transformations & PNG_INTERLACE) != 0)
      {
         png_ptr->pass++;
      }
@@ -2099,7 +2104,7 @@ png_write_finish_row(png_structrp png_ptr)
                png_pass_ystart[png_ptr->pass]) /
                png_pass_yinc[png_ptr->pass];

-            if (png_ptr->transformations & PNG_INTERLACE)
+            if ((png_ptr->transformations & PNG_INTERLACE) != 0)
               break;

         } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
@@ -2309,7 +2314,8 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
 * been specified by the application, and then writes the row out with the
 * chosen filter.
 */
-static void png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
+static void
+png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
   png_size_t row_bytes);

 #define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
@@ -2377,7 +2383,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   /* We don't need to test the 'no filter' case if this is the only filter
    * that has been chosen, as it doesn't actually do anything to the data.
    */
-   if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE)
+   if ((filter_to_do & PNG_FILTER_NONE) != 0 && filter_to_do != PNG_FILTER_NONE)
   {
      png_bytep rp;
      png_uint_32 sum = 0;
@@ -2453,7 +2459,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->sub_row;
   }

-   else if (filter_to_do & PNG_FILTER_SUB)
+   else if ((filter_to_do & PNG_FILTER_SUB) != 0)
   {
      png_bytep rp, dp, lp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2574,7 +2580,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->up_row;
   }

-   else if (filter_to_do & PNG_FILTER_UP)
+   else if ((filter_to_do & PNG_FILTER_UP) != 0)
   {
      png_bytep rp, dp, pp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2688,7 +2694,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->avg_row;
   }

-   else if (filter_to_do & PNG_FILTER_AVG)
+   else if ((filter_to_do & PNG_FILTER_AVG) != 0)
   {
      png_bytep rp, dp, pp, lp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2790,7 +2796,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
   }

   /* Paeth filter */
-   if (filter_to_do == PNG_FILTER_PAETH)
+   if ((filter_to_do == PNG_FILTER_PAETH) != 0)
   {
      png_bytep rp, dp, pp, cp, lp;
      png_size_t i;
@@ -2829,7 +2835,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      best_row = png_ptr->paeth_row;
   }

-   else if (filter_to_do & PNG_FILTER_PAETH)
+   else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
   {
      png_bytep rp, dp, pp, cp, lp;
      png_uint_32 sum = 0, lmins = mins;
@@ -2899,7 +2905,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
 #endif
         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
-#else /* PNG_SLOW_PAETH */
+#else /* SLOW_PAETH */
         p = a + b - c;
         pa = abs(p - a);
         pb = abs(p - b);
@@ -2913,7 +2919,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)

         else
            p = c;
-#endif /* PNG_SLOW_PAETH */
+#endif /* SLOW_PAETH */

         v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);

@@ -2962,7 +2968,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
         best_row = png_ptr->paeth_row;
      }
   }
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */

   /* Do the actual writing of the filtered row data from the chosen filter. */
   png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
@@ -2982,7 +2988,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
      png_ptr->prev_filters[j] = best_row[0];
   }
 #endif
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+#endif /* WRITE_FILTER */
 }


@@ -3018,6 +3024,6 @@ png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
   {
      png_write_flush(png_ptr);
   }
-#endif
+#endif /* WRITE_FLUSH */
 }
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* WRITE */
--- a/projects/vstudio/readme.txt
+++ b/projects/vstudio/readme.txt
@@ -1,7 +1,7 @@

 VisualStudio instructions

-libpng version 1.6.9beta02 - January 1, 2014
+libpng version 1.6.15 - November 20, 2014

 Copyright (c) 1998-2010 Glenn Randers-Pehrson

--- a/projects/vstudio/zlib.props
+++ b/projects/vstudio/zlib.props
@@ -2,7 +2,7 @@
 <!--
 * zlib.props - location of zlib source
 *
- * libpng version 1.6.9beta02 - January 1, 2014
+ * libpng version 1.6.15 - November 20, 2014
 *
 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
 *
@@ -24,7 +24,7 @@
 	 source.

 	 If you use a relative directory name (as below) then it must be
-	 relative to the project directories; these are one level deepers than
+	 relative to the project directories; these are one level deeper than
 	 the directories containing this file.

 	 If the version of zlib you use does not match that used when the
@@ -32,7 +32,7 @@
 	 versions do not match.  The zlib version used in this build is recorded
 	 below:
     -->
-    <ZLibSrcDir>..\..\..\..\zlib-1.2.5</ZLibSrcDir>
+    <ZLibSrcDir>..\..\..\..\zlib-1.2.8</ZLibSrcDir>

    <!-- The following line allows compilation for an ARM target with Visual
         Studio 2012.  Notice that this is not supported by the Visual Studio
--- a/scripts/README.txt
+++ b/scripts/README.txt
@@ -1,9 +1,9 @@

-Makefiles for  libpng version 1.6.9beta02 - January 1, 2014
+Makefiles for  libpng version 1.6.15 - November 20, 2014

 pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng16.so.16.1.6.9beta02)
+                       (gcc, creates libpng16.so.16.1.6.15)
 makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
 makefile.knr      =>  Archaic UNIX Makefile that converts files with
                       ansi2knr (Requires ansi2knr.c from
@@ -19,8 +19,6 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.darwin   =>  Darwin makefile, can use on MacosX
 makefile.dec      =>  DEC Alpha UNIX makefile
 makefile.dj2      =>  DJGPP 2 makefile
- makefile.elf      =>  Linux/ELF makefile symbol versioning,
-                       (gcc, creates libpng16.so.16.1.6.9beta02)
 makefile.freebsd  =>  FreeBSD makefile
 makefile.gcc      =>  Generic gcc makefile
 makefile.hpgcc    =>  HPUX makefile using gcc
@@ -35,12 +33,12 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.os2      =>  OS/2 Makefile (gcc and emx, requires libpng.def)
 makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
 makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng16.so.16.1.6.9beta02)
+                       creates libpng16.so.16.1.6.15)
 makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
 makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng16.so.16.1.6.9beta02)
+                       creates libpng16.so.16.1.6.15)
 makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng16.so.16.1.6.9beta02)
+                       creates libpng16.so.16.1.6.15)
 makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
 makefile.sunos    =>  Sun makefile
 makefile.32sunu   =>  Sun Ultra 32-bit makefile
--- a/scripts/def.dfn
+++ b/scripts/def.dfn
@@ -21,7 +21,7 @@ PNG_DFN "OS2 DESCRIPTION "PNG image compression library""
 PNG_DFN "OS2 CODE PRELOAD MOVEABLE DISCARDABLE"
 PNG_DFN ""
 PNG_DFN "EXPORTS"
-PNG_DFN ";Version 1.6.9beta02"
+PNG_DFN ";Version 1.6.15"

 #define PNG_EXPORTA(ordinal, type, name, args, attributes)\
        PNG_DFN "@" SYMBOL_PREFIX "@@" name "@"
--- a/scripts/descrip.mms
+++ b/scripts/descrip.mms
@@ -33,20 +33,20 @@ clean :


 # Other dependencies.
-png.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngpread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngset.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngget.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngrtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngrutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngerror.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngmem.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngrio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngwio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngtrans.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngwrite.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngwtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
-pngwutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,             pnginfo.h, pngdebug.h
+png.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngpread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngset.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngget.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngerror.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngmem.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwio.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngtrans.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwrite.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h

-pngtest.obj : png.h, pngconf.h
+pngtest.obj : png.h, pngconf.h, pnglibconf.h
--- a/scripts/dfn.awk
+++ b/scripts/dfn.awk
@@ -1,9 +1,9 @@
 #!/bin/awk -f
 # scripts/dfn.awk - process a .dfn file
 #
-# last changed in libpng version 1.5.14 - February 4, 2013
+# last changed in libpng version 1.5.19 - August 21, 2014
 #
-# Copyright (c) 2013-2013 Glenn Randers-Pehrson
+# Copyright (c) 2013-2014 Glenn Randers-Pehrson
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -25,7 +25,7 @@ BEGIN{
 # The output file must be specified before any input:
 NR==1 && out == "/dev/null" {
   print "out=output.file must be given on the command line"
-   # but continue without setting the error code, this allows the
+   # but continue without setting the error code; this allows the
   # script to be checked easily
 }

@@ -61,14 +61,14 @@ $1 ~ /^PNG_DFN_END_SORT/{
 }

 /^[^"]*PNG_DFN *".*"[^"]*$/{
-   # A definition line, apparently correctly formated, extract the
+   # A definition line, apparently correctly formatted; extract the
   # definition then replace any doubled "" that remain with a single
   # double quote.  Notice that the original doubled double quotes
   # may have been split by tokenization
   #
-   # Sometimes GCC splits the PNG_DFN lines, we know this has happened
+   # Sometimes GCC splits the PNG_DFN lines; we know this has happened
   # if the quotes aren't closed and must read another line.  In this
-   # case it is essential to reject lines that start '#' because those
+   # case it is essential to reject lines that start with '#' because those
   # are introduced #line directives.
   orig=$0
   line=$0
@@ -126,13 +126,13 @@ $1 ~ /^PNG_DFN_END_SORT/{
         else while (1) {
            if (getline nextline) {
               # If the line starts with '#' it is a preprocesor line directive
-               # from cc -E, skip it:
+               # from cc -E; skip it:
               if (nextline !~ /^#/) {
                  line = line " " nextline
                  break
               }
            } else {
-               # This is end-of-input - probably a missig "@ on the first line:
+               # This is end-of-input - probably a missing "@ on the first line:
               print "line", lineno ": unbalanced @\" ... \"@ pair"
               err=1
               next
@@ -144,7 +144,7 @@ $1 ~ /^PNG_DFN_END_SORT/{
      }

      # Attempt to remove a trailing " (not preceded by '@') - if this can
-      # be done stop now, if not assume a split line again
+      # be done, stop now; if not assume a split line again
      if (sub(/"[^"]*$/, "", line))
         break

@@ -189,7 +189,7 @@ $1 ~ /^PNG_DFN_END_SORT/{
   next
 }

-/PNG_DFN/{
+/PNG_DFN/{
   print "line", NR, "incorrectly formatted PNG_DFN line:"
   print $0
   err = 1
--- a/scripts/intprefix.dfn
+++ b/scripts/intprefix.dfn
@@ -15,5 +15,8 @@
 #define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
        PNG_DFN "@" name "@"

+#define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
+        PNG_DFN "@" name "@"
+
 #define PNGPREFIX_H /* self generation */
 #include "../pngpriv.h"
--- a/scripts/libpng-config-body.in
+++ b/scripts/libpng-config-body.in
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -11,7 +11,7 @@

 # Modeled after libxml-config.

-version=1.6.9beta02
+version=1.6.15
 prefix=""
 libdir=""
 libs=""
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -5,6 +5,6 @@ includedir=@includedir@/libpng16

 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.6.9beta02
+Version: 1.6.15
 Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}
--- a/scripts/makefile.32sunu
+++ b/scripts/makefile.32sunu
@@ -1,6 +1,6 @@
 # makefile for libpng on Solaris 2.x with cc
 # Contributed by William L. Sebok, based on makefile.linux
-# Copyright (C) 2002, 2006, 2010-2011 Glenn Randers-Pehrson
+# Copyright (C) 2002, 2006, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1998 Greg Roelofs
 # Copyright (C) 1996, 1997 Andreas Dilger

@@ -45,8 +45,8 @@ ZLIBINC=/usr/include
 WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wmissing-declarations -Wtraditional -Wcast-align \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) $(SUN_CC_FLAGS) \
-	# $(WARNMORE) -g -DPNG_DEBUG=5
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=$(SUN_CC_FLAGS) # $(WARNMORE) -g
 LDFLAGS=$(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) libpng.a -lz -lm

 INCPATH=$(prefix)/include
@@ -77,8 +77,11 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 .SUFFIXES:      .c .o .pic.o

+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
 .c.pic.o:
-	$(CC) -c $(CFLAGS) -KPIC -o $@ $*.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c

 all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config

@@ -104,8 +107,8 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo ccopts=\"-xtarget=ultra\"; \
-	echo ldopts=\"-xtarget=ultra\"; \
+	echo ccopts=\"-fast -xtarget=ultra\"; \
+	echo ldopts=\"-fast -xtarget=ultra\"; \
 	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config
@@ -196,7 +199,7 @@ install: install-static install-shared install-man install-config
 test-dd:
 	echo
 	echo Testing installed dynamic shared library in $(DL).
-	$(CC) $(SUN_CC_FLAGS) -I$(DI) -I$(ZLIBINC) \
+	$(CC) $(SUN_CC_FLAGS) -I$(DI) $(CPPFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -o pngtestd -L$(DL) -R$(DL) `$(BINPATH)/$(LIBNAME)-config --ldflags` \
 	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
@@ -205,7 +208,7 @@ test-dd:
 test-installed:
 	echo
 	echo Testing installed dynamic shared library.
-	$(CC) $(SUN_CC_FLAGS) -I$(ZLIBINC) \
+	$(CC) $(SUN_CC_FLAGS) $(CPPFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
 	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
@@ -222,20 +225,20 @@ writelock:

 # DO NOT DELETE THIS LINE -- make depend depends on it.

-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h

 pngtest.o: png.h pngconf.h pnglibconf.h
--- a/scripts/makefile.64sunu
+++ b/scripts/makefile.64sunu
@@ -1,6 +1,6 @@
 # makefile for libpng on Solaris 2.x with cc
 # Contributed by William L. Sebok, based on makefile.linux
-# Copyright (C) 2002, 2006, 2010-2011 Glenn Randers-Pehrson
+# Copyright (C) 2002, 2006, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1998 Greg Roelofs
 # Copyright (C) 1996, 1997 Andreas Dilger

@@ -45,8 +45,8 @@ ZLIBINC=/usr/include
 WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wmissing-declarations -Wtraditional -Wcast-align \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) $(SUN_CC_FLAGS) \
-	# $(WARNMORE) -g -DPNG_DEBUG=5
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS= $(SUN_CC_FLAGS) # $(WARNMORE) -g
 LDFLAGS=-L. -R. $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
@@ -77,8 +77,11 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 .SUFFIXES:      .c .o .pic.o

+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
 .c.pic.o:
-	$(CC) -c $(CFLAGS) -KPIC -o $@ $*.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c

 all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config

@@ -104,8 +107,8 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo ccopts=\"-xtarget=ultra -xarch=v9\"; \
-	echo ldopts=\"-xtarget=ultra -xarch=v9\"; \
+	echo ccopts=\"-fast -xtarget=ultra -xarch=v9\"; \
+	echo ldopts=\"-fast -xtarget=ultra -xarch=v9\"; \
 	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config
@@ -196,7 +199,7 @@ install: install-static install-shared install-man install-config
 test-dd:
 	echo
 	echo Testing installed dynamic shared library in $(DL).
-	$(CC) $(SUN_CC_FLAGS) -I$(DI) -I$(ZLIBINC) \
+	$(CC) $(SUN_CC_FLAGS) -I$(DI) $(CPPFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -o pngtestd -L$(DL) -R$(DL) `$(BINPATH)/$(LIBNAME)-config --ldflags` \
 	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
@@ -205,7 +208,7 @@ test-dd:
 test-installed:
 	echo
 	echo Testing installed dynamic shared library.
-	$(CC) $(SUN_CC_FLAGS) -I$(ZLIBINC) \
+	$(CC) $(SUN_CC_FLAGS) $(CPPFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags` \
 	   $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB)
@@ -222,20 +225,20 @@ writelock:

 # DO NOT DELETE THIS LINE -- make depend depends on it.

-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h

 pngtest.o: png.h pngconf.h pnglibconf.h
--- a/scripts/makefile.aix
+++ b/scripts/makefile.aix
@@ -1,5 +1,5 @@
 # makefile for libpng using gcc (generic, static library)
-# Copyright (C) 2002, 2006-2009 Glenn Randers-Pehrson
+# Copyright (C) 2002, 2006-2009, 2014 Glenn Randers-Pehrson
 # Copyright (C) 2000 Cosmin Truta
 # Copyright (C) 2000 Marc O. Gloor (AIX support added, from makefile.gcc)
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
@@ -21,7 +21,7 @@ RANLIB = ranlib
 RM_F = rm -f
 LN_SF = ln -f -s

-LIBNAME=libpng16
+LIBNAME = libpng16
 PNGMAJ = 16

 prefix=/usr/local
@@ -41,42 +41,37 @@ DESTDIR=
 DI=$(DESTDIR)$(INCPATH)
 DL=$(DESTDIR)$(LIBPATH)

-CDEBUG = -g -DPNG_DEBUG=5
-LDDEBUG =
-CRELEASE = -O2
-LDRELEASE = -s
-WARNMORE=-W -Wall
-CFLAGS = -I$(ZLIBINC) $(WARNMORE) $(CRELEASE)
-LDFLAGS = -L. -L$(ZLIBLIB) -lpng16 -lz -lm $(LDRELEASE)
-
-# File extensions
-O=.o
-A=.a
-E=
+WARNMORE =
+CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS = -W -Wall -O2 # $(WARNMORE) -g
+LDFLAGS = -L. -L$(ZLIBLIB) -lpng16 -lz -lm

 # Variables
-OBJS =  png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O) \
-	pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O) \
-	pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
+OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
+	pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+	pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o

 # Targets
-all: $(LIBNAME)$(A) pngtest$(E)
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: $(LIBNAME).a pngtest$(E)

 include scripts/pnglibconf.mak
 REMOVE = $(RM_F)
 DFNFLAGS = $(DEFS) $(CPPFLAGS)

-$(LIBNAME)$(A): $(OBJS)
+$(LIBNAME).a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
 	$(RANLIB) $@

 test: pngtest$(E)
 	./pngtest$(E)

-pngtest$(E): pngtest$(O) $(LIBNAME)$(A)
-	$(LD) -o $@ pngtest$(O) $(LDFLAGS)
+pngtest$(E): pngtest.o $(LIBNAME).a
+	$(LD) -o $@ pngtest.o $(LDFLAGS)

-install: $(LIBNAME)$(A)
+install: $(LIBNAME).a
 	-@if [ ! -d $(DI)  ]; then $(MKDIR_P) $(DI); fi
 	-@if [ ! -d $(DI)/$(LIBNAME)  ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
 	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
@@ -92,30 +87,30 @@ install: $(LIBNAME)$(A)
 	$(DI)/$(LIBNAME)/pnglibconf.h
 	-@$(RM_F) -r $(DI)/libpng
 	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-	-@$(RM_F) $(DL)/$(LIBNAME)$(A)
-	-@$(RM_F) $(DL)/libpng$(A)
-	cp $(LIBNAME)$(A) $(DL)/$(LIBNAME)$(A)
-	chmod 644 $(DL)/$(LIBNAME)$(A)
-	(cd $(DL); $(LN_SF) $(LIBNAME)$(A) libpng$(A))
+	-@$(RM_F) $(DL)/$(LIBNAME).a
+	-@$(RM_F) $(DL)/libpng.a
+	cp $(LIBNAME).a $(DL)/$(LIBNAME).a
+	chmod 644 $(DL)/$(LIBNAME).a
+	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
 	(cd $(DI); $(LN_SF) libpng/* .;)

 clean:
-	$(RM_F) *.o $(LIBNAME)$(A) pngtest pngout.png pnglibconf.h
+	$(RM_F) *.o $(LIBNAME).a pngtest pngout.png pnglibconf.h

-png$(O):      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread$(O):  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h

-pngtest$(O):  png.h pngconf.h pnglibconf.h
+pngtest.o:  png.h pngconf.h pnglibconf.h
--- a/scripts/makefile.amiga
+++ b/scripts/makefile.amiga
@@ -24,13 +24,15 @@ LDLIBS= libpng.lib libgz.lib LIB:scm.lib LIB:sc.lib Lib:amiga.lib
 LN= slink
 # file deletion command
 RM= delete quiet
-# file copy command?
-CP= copy
 # library (.lib) file creation command
 AR= oml
 # make directory command
 MKDIR= makedir

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
 	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
 	pngwtran.o pngmem.o pngerror.o pngpread.o
@@ -43,8 +45,8 @@ $(AR) libpng.lib r $(OBJS)

 $(OBJS): pngpriv.h png.h pngconf.h pnglibconf.h pnginfo.h pngstruct.h pngdebug.h

-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-$(CP) scripts/pnglibconf.h.prebuilt pnglibconf.h
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+COPY $(PNGLIBCONF_H_PREBUILT) TO pnglibconf.h

 pngtest: pngtest.o libpng.lib
 $(LN) <WITH <
--- a/scripts/makefile.atari
+++ b/scripts/makefile.atari
@@ -1,5 +1,5 @@
 # makefile for libpng
-# Copyright (C) 2002 Glenn Randers-Pehrson
+# Copyright (C) 2002, 2014 Glenn Randers-Pehrson
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
 #
 # This code is released under the libpng license.
@@ -9,9 +9,10 @@
 # Modified for LC56/ATARI assumes libz.lib is in same dir and uses default
 # rules for library management
 #
-CFLAGS=-I..\zlib -O
+CPPFLAGS = -I..\zlib
+CFLAGS = -O
 LBR = png.lib
-LDFLAGS=-lpng -lz -lm
+LDFLAGS = -L. -L..\zlib -lpng -lz -lm

 # where make install puts libpng.a and png.h
 prefix=/usr/local
@@ -28,6 +29,10 @@ LIBPATH=$(prefix)/lib
 # you execute make install.
 DESTDIR=

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 OBJS = $(LBR)(png.o) $(LBR)(pngset.o) $(LBR)(pngget.o) $(LBR)(pngrutil.o)\
 	$(LBR)(pngtrans.o) $(LBR)(pngwutil.o)\
 	$(LBR)(pngread.o) $(LBR)(pngerror.o) $(LBR)(pngwrite.o)\
@@ -36,12 +41,15 @@ OBJS = $(LBR)(png.o) $(LBR)(pngset.o) $(LBR)(pngget.o) $(LBR)(pngrutil.o)\

 all: $(LBR) pngtest.ttp

+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
 $(LBR): $(OBJS)

 $(OBJS): pngpriv.h png.h pngconf.h pnglibconf.h pnginfo.h pngstruct.h pngdebug.h

-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt pnglibconf.h
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	cp $(PNGLIBCONF_H_PREBUILT) $@

 pngtest.ttp: pngtest.o $(LBR)
 	$(CC) $(CFLAGS) $(LDFLAGS) -o$@ pngtest.o
--- a/scripts/makefile.bc32
+++ b/scripts/makefile.bc32
@@ -11,10 +11,11 @@
 ## Where zlib.h, zconf.h and zlib.lib are
 ZLIB_DIR=..\zlib

-## Compiler, linker and lib stuff
+## Compiler, linker, librarian and other tools
 CC=bcc32
 LD=bcc32
 LIB=tlib
+CP=copy

 # -3 = 386, -4 = 486, -5 = Pentium etc.
 !ifndef TARGET_CPU
@@ -43,11 +44,18 @@ LDEBUG=$(LDEBUG) -N
 # -d  merge duplicate strings
 # -k- turn off standard stack frame
 # -w  display all warnings
-CFLAGS=-I$(ZLIB_DIR) -O2 -d -k- -w $(TARGET_CPU) $(CDEBUG)
+CPPFLAGS=-I$(ZLIB_DIR)
+CFLAGS=-O2 -d -k- -w $(TARGET_CPU) $(CDEBUG)

 # -M  generate map file
 LDFLAGS=-L$(ZLIB_DIR) -M $(LDEBUG)

+# Pre-built configuration
+# See scripts\pnglibconf.mak for more options
+!ifndef PNGLIBCONF_H_PREBUILT
+PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
+!endif
+
 ## Variables
 OBJS = \
 	png.obj \
@@ -89,10 +97,11 @@ LIBNAME=libpng.lib
 # Braces let make "batch" calls to the compiler,
 # 2 calls instead of 12; space is important.
 .c.obj:
-	$(CC) $(CFLAGS) -c {$*.c }
+	$(CC) $(CPPFLAGS) $(CFLAGS) -c {$*.c }

 .c.exe:
-	$(CC) $(CFLAGS) $(LDFLAGS) $*.c $(LIBNAME) zlib.lib $(NOEHLIB)
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $*.c \
+	  $(LIBNAME) zlib.lib $(NOEHLIB)

 .obj.exe:
 	$(LD) $(LDFLAGS) $*.obj $(LIBNAME) zlib.lib $(NOEHLIB)
@@ -109,26 +118,24 @@ test: pngtest.exe

 ## Minor Targets

-# see scripts\pnglibconf.mak for how to make this file
-# with different options
-pnglibconf.h: scripts\pnglibconf.h.prebuilt
-	copy scripts\pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@

-png.obj: png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror.obj: pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget.obj: pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem.obj: pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread.obj: pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread.obj: pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio.obj: pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran.obj: pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil.obj: pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset.obj: pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans.obj: pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio.obj: pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite.obj: pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran.obj: pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil.obj: pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+png.obj: png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.obj: pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.obj: pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.obj: pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.obj: pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.obj: pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.obj: pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.obj: pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.obj: pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.obj: pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.obj: pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.obj: pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.obj: pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.obj: pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.obj: pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 pngtest.obj: pngtest.c png.h pngconf.h pnglibconf.h

 $(LIBNAME): $(OBJS)
--- a/scripts/makefile.beos
+++ b/scripts/makefile.beos
@@ -1,6 +1,6 @@
 # makefile for libpng on BeOS x86 ELF with gcc
 # modified from makefile.linux by Sander Stoks
-# Copyright (C) 2002, 2006, 2008, 2010-2011 Glenn Randers-Pehrson
+# Copyright (C) 2002, 2006, 2008, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1999 Greg Roelofs
 # Copyright (C) 1996, 1997 Andreas Dilger
 #
@@ -24,6 +24,7 @@ AR_RC=ar rc
 MKDIR_P=mkdir -p
 LN_SF=ln -sf
 RANLIB=ranlib
+CP=cp
 RM_F=/bin/rm -f

 # Where the zlib library and include files are located
@@ -40,8 +41,8 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \

 # On BeOS, -O1 is actually better than -O3.  This is a known bug but it's
 # still here in R4.5
-CFLAGS=-I$(ZLIBINC) -W -Wall -O1 -funroll-loops \
-	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-W -Wall -O1 -funroll-loops $(ALIGN) # $(WARNMORE) -g
 # LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng -lz
 LDFLAGS=-L. -Wl,-soname=$(LIBSOMAJ) -L$(ZLIBLIB) -lz

@@ -68,6 +69,10 @@ DI=$(DESTDIR)$(INCPATH)
 DL=$(DESTDIR)$(LIBPATH)
 DM=$(DESTDIR)$(MANPATH)

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
 	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
 	pngwtran.o pngmem.o pngerror.o pngpread.o
@@ -76,11 +81,13 @@ OBJSDLL = $(OBJS)

 .SUFFIXES:      .c .o

+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
 all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config

-# try include scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -176,14 +183,14 @@ install: install-static install-shared install-man install-config
 test-dd:
 	echo
 	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) $(CFLAGS) \
+	$(CC) -I$(DI) $(CPPFLAGS) $(CFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -L$(DL) -L$(ZLIBLIB) -Wl,-rpath $(ZLIBLIB):$(DL) \
 	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
 	./pngtestd pngtest.png

 test-installed:
-	$(CC) $(CFLAGS) \
+	$(CC) $(CPPFLAGS) $(CFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
 	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
@@ -196,20 +203,20 @@ clean:

 # DO NOT DELETE THIS LINE -- make depend depends on it.

-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h

 pngtest.o: png.h pngconf.h pnglibconf.h
--- a/scripts/makefile.bor
+++ b/scripts/makefile.bor
@@ -12,10 +12,11 @@
 ## Where zlib.h, zconf.h and zlib_MODEL.lib are
 ZLIB_DIR=..\zlib

-## Compiler, linker and lib stuff
+## Compiler, linker, librarian and other tools
 CC=bcc
 LD=bcc
 LIB=tlib
+CP=copy

 !ifndef MODEL
 MODEL=l
@@ -51,11 +52,18 @@ LDEBUG=$(LDEBUG) -N
 # -w  set all warnings on
 # -O2 optimize for speed
 # -Z  global optimization
-CFLAGS=-O2 -Z -X- -w -I$(ZLIB_DIR) -$(TARGET_CPU) $(MODEL_ARG) $(CDEBUG)
+CPPFLAGS=-I$(ZLIB_DIR)
+CFLAGS=-O2 -Z -X- -w -$(TARGET_CPU) $(MODEL_ARG) $(CDEBUG)

 # -M  generate map file
 LDFLAGS=-M -L$(ZLIB_DIR) $(MODEL_ARG) $(LDEBUG)

+# Pre-built configuration
+# See scripts\pnglibconf.mak for more options
+!ifndef PNGLIBCONF_H_PREBUILT
+PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
+!endif
+
 ## Variables

 OBJS = \
@@ -99,18 +107,19 @@ LIBNAME=libpng$(MODEL).lib
 # Braces let make "batch" calls to the compiler,
 # 2 calls instead of 12; space is important.
 .c.obj:
-	$(CC) $(CFLAGS) -c {$*.c }
+	$(CC) $(CPPFLAGS) $(CFLAGS) -c {$*.c }

 .c.exe:
-	$(CC) $(CFLAGS) $(LDFLAGS) $*.c $(LIBNAME) zlib_$(MODEL).lib $(NOEHLIB)
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $*.c \
+	  $(LIBNAME) zlib_$(MODEL).lib $(NOEHLIB)

 ## Major targets

 all: libpng pngtest

-# try !inlude scripts\pnglibconf.mak for more options
-pnglibconf.h: scripts\pnglibconf.h.prebuilt
-	copy scripts\pnglibconf.h.prebuilt $@
+# try !include scripts\pnglibconf.mak for more options
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@

 libpng: $(LIBNAME)

@@ -121,21 +130,21 @@ test: pngtest$(MODEL).exe

 ## Minor Targets

-png.obj: png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror.obj: pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget.obj: pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem.obj: pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread.obj: pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread.obj: pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio.obj: pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran.obj: pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil.obj: pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset.obj: pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans.obj: pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio.obj: pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite.obj: pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran.obj: pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil.obj: pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+png.obj: png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.obj: pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.obj: pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.obj: pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.obj: pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.obj: pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.obj: pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.obj: pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.obj: pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.obj: pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.obj: pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.obj: pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.obj: pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.obj: pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.obj: pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h

 $(LIBNAME): $(OBJS)
 	-del $(LIBNAME)
--- a/scripts/makefile.cegcc
+++ b/scripts/makefile.cegcc
@@ -23,14 +23,14 @@

 VERMAJ = 1
 VERMIN = 6
-VERMIC = 9
+VERMIC = 15
 VER = $(VERMAJ).$(VERMIN).$(VERMIC)
 NAME = libpng
 PACKAGE = $(NAME)-$(VER)

 BIN = libpng16-0.dll
 LIB = libpng16.a libpng16.dll.a libpng.a libpng.dll.a
-INCLUDE = png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+INCLUDE = png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 PC = libpng16.pc libpng.pc

 MANIFESTVERBIN = "Libpng-$(VER): Binary files"
--- a/scripts/makefile.darwin
+++ b/scripts/makefile.darwin
@@ -1,5 +1,5 @@
 # makefile for libpng on Darwin / Mac OS X
-# Copyright (C) 2002, 2004, 2006, 2008, 2010-2011 Glenn Randers-Pehrson
+# Copyright (C) 2002, 2004, 2006, 2008, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 2001 Christoph Pfisterer
 # derived from makefile.linux:
 #  Copyright (C) 1998, 1999 Greg Roelofs
@@ -34,12 +34,13 @@ AR_RC=ar rc
 MKDIR_P=mkdir -p
 LN_SF=ln -sf
 RANLIB=ranlib
+CP=cp
 RM_F=/bin/rm -f
-ARCH=-arch ppc -arch i386 -arch x86_64

-# CFLAGS=-I$(ZLIBINC) -W -Wall -O3 -funroll-loops
-CFLAGS=-I$(ZLIBINC) -W -Wall -O -funroll-loops $(ARCH)
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz $(ARCH)
+CPPFLAGS=-I$(ZLIBINC)
+# CFLAGS=-W -Wall -O3 -funroll-loops
+CFLAGS=-W -Wall -O -funroll-loops
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -61,6 +62,10 @@ DI=$(DESTDIR)$(INCPATH)
 DL=$(DESTDIR)$(LIBPATH)
 DM=$(DESTDIR)$(MANPATH)

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
 	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
 	pngwtran.o pngmem.o pngerror.o pngpread.o
@@ -69,14 +74,16 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 .SUFFIXES:      .c .o .pic.o

+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
 .c.pic.o:
-	$(CC) -c $(CFLAGS) -fno-common -o $@ $*.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fno-common -o $@ $*.c

 all: libpng.a $(LIBSO) pngtest libpng.pc libpng-config

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -105,7 +112,7 @@ $(LIBSOMAJ): $(OBJSDLL)
 	$(CC) -dynamiclib \
 	 -install_name $(LIBPATH)/$(LIBSOMAJ) \
 	 -current_version 16 -compatibility_version 16 \
-	 $(ARCH) -o $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) \
 	 $(OBJSDLL) -L$(ZLIBLIB) -lz

 pngtest: pngtest.o $(LIBSO)
@@ -176,14 +183,14 @@ install: install-static install-shared install-man install-config
 test-dd:
 	echo
 	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
+	$(CC) -I$(DI) $(CPPFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -L$(DL) -L$(ZLIBLIB) \
 	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
 	./pngtestd pngtest.png

 test-installed:
-	$(CC) $(CFLAGS) \
+	$(CC) $(CPPFLAGS) $(CFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -L$(ZLIBLIB) \
 	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
@@ -199,20 +206,20 @@ writelock:

 # DO NOT DELETE THIS LINE -- make depend depends on it.

-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h

 pngtest.o: png.h pngconf.h pnglibconf.h
--- a/scripts/makefile.dec
+++ b/scripts/makefile.dec
@@ -1,5 +1,5 @@
 # makefile for libpng on DEC Alpha Unix
-# Copyright (C) 2000-2002, 2006, 2010-2011 Glenn Randers-Pehrson
+# Copyright (C) 2000-2002, 2006, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
 #
 # This code is released under the libpng license.
@@ -22,6 +22,7 @@ CC=cc
 MKDIR_P=mkdir
 LN_SF=ln -f -s
 RANLIB=ranlib
+CP=cp
 RM_F=/bin/rm -f

 # where make install puts libpng.a and png.h
@@ -53,18 +54,25 @@ DM=$(DESTDIR)$(MANPATH)
 ZLIBLIB=../zlib
 ZLIBINC=../zlib

-CFLAGS=-std -w1 -I$(ZLIBINC) -O # -g -DPNG_DEBUG=1
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-std -w1 -O # -g
 LDFLAGS=-L$(ZLIBLIB) -rpath $(ZLIBLIB) libpng.a -lz -lm

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
 	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
 	pngwtran.o pngmem.o pngerror.o pngpread.o

+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
 all: $(LIBSO) libpng.a pngtest libpng.pc libpng-config

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@  $(OBJS)
@@ -161,7 +169,7 @@ install: install-static install-shared install-man install-config
 test-dd:
 	echo
 	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -w1 -I$(DI) -I$(ZLIBINC) \
+	$(CC) -w1 -I$(DI) $(CPPFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -L$(DL) -L$(ZLIBLIB)  -R$(ZLIBLIB) -R$(DL) \
 	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
@@ -170,33 +178,33 @@ test-dd:
 test-installed:
 	echo
 	echo Testing installed dynamic shared library.
-	$(CC) -w1 -I$(ZLIBINC) \
+	$(CC) -w1 $(CPPFLAGS) \
 	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
 	   -L$(ZLIBLIB) -R$(ZLIBLIB) \
 	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
 	./pngtesti pngtest.png

 clean:
-	/bin/rm -f *.o libpng.a pngtest pngtesti pngout.png \
+	$(RM_F) *.o libpng.a pngtest pngtesti pngout.png \
 	libpng-config $(LIBSO) $(LIBSOMAJ)* \
 	libpng.pc pnglibconf.h

 # DO NOT DELETE THIS LINE -- make depend depends on it.

-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h

 pngtest.o: png.h pngconf.h pnglibconf.h
--- a/scripts/makefile.dj2
+++ b/scripts/makefile.dj2
@@ -1,5 +1,5 @@
 # DJGPP (DOS gcc) makefile for libpng
-# Copyright (C) 2002, 2006, 2009-2010-2011 Glenn Randers-Pehrson
+# Copyright (C) 2002, 2006, 2009-2014 Glenn Randers-Pehrson
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
 #
 # This code is released under the libpng license.
@@ -13,20 +13,30 @@ INCPATH=$(prefix)/include
 LIBPATH=$(prefix)/lib

 CC=gcc
-CFLAGS=-I../zlib -O -DPNG_NO_SNPRINTF
+CPPFLAGS=-I../zlib -DPNG_NO_SNPRINTF
+CFLAGS=-O
 LDFLAGS=-L. -L../zlib/ -lpng -lz -lm

 RANLIB=ranlib

+CP=cp
+RM_F=rm -f
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
 	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o pngwtran.o \
 	pngmem.o pngerror.o pngpread.o

+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
 all: libpng.a pngtest

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@

 libpng.a: $(OBJS)
 	ar rc $@  $(OBJS)
@@ -39,24 +49,24 @@ pngtest: pngtest.o libpng.a
 test: pngtest
 	./pngtest
 clean:
-	rm -f *.o libpng.a pngtest pngout.png pnglibconf.h
+	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.h

 # DO NOT DELETE THIS LINE -- make depend depends on it.

-png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+png.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h

 pngtest.o: png.h pngconf.h pnglibconf.h
--- a/scripts/makefile.elf
+++ b/scripts/makefile.elf
@@ -1,263 +0,0 @@
-# makefile for libpng.a and libpng16.so on Linux ELF with gcc
-# Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2011 Greg Roelofs
-# and Glenn Randers-Pehrson
-# Copyright (C) 1996, 1997 Andreas Dilger
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# Modified for Debian by Junichi Uekawa and Josselin Mouette
-# Major modifications are:
-#    * link libpng explicitly with libz and libm
-#    * $(OLDSO).16 is a symlink rather than a different library
-#    * versioned symbols
-
-# Library name:
-LIBNAME = libpng16
-PNGMAJ = 16
-
-# Shared library names:
-LIBSO=$(LIBNAME).so
-LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
-LIBSOREL=$(LIBSOMAJ).$(RELEASE)
-OLDSO=libpng.so
-OLDSOMAJ=libpng.so.16
-
-# Utilities:
-AR_RC=ar rc
-CC=gcc
-MKDIR_P=mkdir -p
-LN_SF=ln -sf
-RANLIB=ranlib
-RM_F=/bin/rm -f
-
-# where "make install" puts libpng16.a, libpng16.so*,
-# libpng16/png.h, libpng16/pngconf.h, and libpng16/pnglibconf.h
-# Prefix must be a full pathname.
-prefix=/usr/local
-exec_prefix=$(prefix)
-
-# Where the zlib library and include files are located.
-ZLIBLIB=/usr/local/lib
-ZLIBINC=/usr/local/include
-# ZLIBLIB=../zlib
-# ZLIBINC=../zlib
-
-ALIGN=
-# for i386:
-#ALIGN=-malign-loops=2 -malign-functions=2
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-	-Wmissing-declarations -Wtraditional -Wcast-align \
-	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-
-# for pgcc version 2.95.1, -O3 is buggy; don't use it.
-
-CFLAGS=-W -Wall -D_REENTRANT -O2 \
-	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
-
-LDFLAGS=-L. -lpng16
-LDFLAGS_A=libpng.a -lz -lm
-LIBADDFLAGS=-lz -lm
-
-
-INCPATH=$(prefix)/include
-LIBPATH=$(exec_prefix)/lib
-MANPATH=$(prefix)/man
-BINPATH=$(exec_prefix)/bin
-
-# override DESTDIR= on the make install command line to easily support
-# installing into a temporary location.  Example:
-#
-#    make install DESTDIR=/tmp/build/libpng
-#
-# If you're going to install into a temporary location
-# via DESTDIR, $(DESTDIR)$(prefix) must already exist before
-# you execute make install.
-DESTDIR=
-
-DB=$(DESTDIR)$(BINPATH)
-DI=$(DESTDIR)$(INCPATH)
-DL=$(DESTDIR)$(LIBPATH)
-DM=$(DESTDIR)$(MANPATH)
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-	pngwtran.o pngmem.o pngerror.o pngpread.o
-
-OBJSDLL = $(OBJS:.o=.pic.o)
-
-.SUFFIXES:      .c .o .pic.o
-
-.c.pic.o:
-	$(CC) -c $(CFLAGS) -fPIC -o $@ $*.c
-
-all: libpng.a $(LIBSO) pngtest pngtest-static libpng.pc libpng-config
-
-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
-
-libpng.a: $(OBJS)
-	$(AR_RC) $@ $(OBJS)
-	$(RANLIB) $@
-
-libpng.pc:
-	cat scripts/libpng.pc.in | sed -e s!@prefix@!$(prefix)! \
-	-e s!@exec_prefix@!$(exec_prefix)! \
-	-e s!@libdir@!$(LIBPATH)! \
-	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc
-
-libpng.syms: png.h pngconf.h pnglibconf.h
-	$(CC) $(CFLAGS) -E -DPNG_BUILDSYMS -DPNG_INTERNAL png.h |\
-	awk -F '[\t [\\]();]' -v PNGMAJ=$(PNGMAJ) 'BEGIN{printf("PNG16_%s {global:\n",PNGMAJ)}\
-	{ for (i=1;i+2<=NF;++i)\
-		if ($$(i)=="PNG_FUNCTION_EXPORT" && $$(i+2)=="END")\
-			print $$(i+1) ";";\
-	for (i=1;i+1<=NF;++i)\
-		if ($$(i)=="PNG_DATA_EXPORT")\
-			print $$(i+1) ";";}\
-	END{print "local: *; };"}' >$@.new
-	$(RM_F) $@
-	mv $@.new $@
-
-libpng-config:
-	( cat scripts/libpng-config-head.in; \
-	echo prefix=\"$(prefix)\"; \
-	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo L_opts=\"\"; \
-	echo R_opts=\"\"; \
-	echo libs=\"-lpng16\"; \
-	echo all_libs=\"-lpng16 $(LIBADDFLAGS)\"; \
-	cat scripts/libpng-config-body.in ) > libpng-config
-	chmod +x libpng-config
-
-$(LIBSO): $(LIBSOMAJ)
-	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
-
-$(LIBSOMAJ): $(OBJSDLL) libpng.syms
-	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) \
-	-Wl,-version-script,libpng.syms \
-	-o $(LIBSOMAJ) \
-	$(OBJSDLL)
-
-pngtest: pngtest.o $(LIBSO)
-	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
-
-pngtest-static: pngtest.o libpng.a
-	$(CC) -o pngtest-static $(CFLAGS) pngtest.o $(LDFLAGS_A)
-
-test: pngtest pngtest-static
-	@echo ""
-	@echo "   Running pngtest dynamically linked with $(LIBSO):"
-	@echo ""
-	LD_LIBRARY_PATH=".:${LD_LIBRARY_PATH}" ./pngtest
-	@echo ""
-	@echo "   Running pngtest statically linked with libpng.a:"
-	@echo ""
-	./pngtest-static
-
-install-headers: png.h pngconf.h pnglibconf.h
-	-@if [ ! -d $(DI) ]; then $(MKDIR_P) $(DI); fi
-	-@if [ ! -d $(DI)/$(LIBNAME) ]; then $(MKDIR_P) $(DI)/$(LIBNAME); fi
-	cp png.h pngconf.h pnglibconf.h $(DI)/$(LIBNAME)
-	chmod 644 $(DI)/$(LIBNAME)/png.h $(DI)/$(LIBNAME)/pngconf.h $(DI)/$(LIBNAME)/pnglibconf.h
-	-@$(RM_F) $(DI)/png.h $(DI)/pngconf.h $(DI)/pnglibconf.h
-	-@$(RM_F) $(DI)/libpng
-	(cd $(DI); $(LN_SF) $(LIBNAME) libpng; $(LN_SF) $(LIBNAME)/* .)
-
-install-static: install-headers libpng.a
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	cp libpng.a $(DL)/$(LIBNAME).a
-	chmod 644 $(DL)/$(LIBNAME).a
-	-@$(RM_F) $(DL)/libpng.a
-	(cd $(DL); $(LN_SF) $(LIBNAME).a libpng.a)
-
-install-shared: install-headers $(LIBSOMAJ) libpng.pc
-	-@if [ ! -d $(DL) ]; then $(MKDIR_P) $(DL); fi
-	-@$(RM_F) $(DL)/$(LIBSO)
-	-@$(RM_F) $(DL)/$(LIBSOREL)
-	-@$(RM_F) $(DL)/$(OLDSO)
-	cp $(LIBSOMAJ) $(DL)/$(LIBSOREL)
-	chmod 755 $(DL)/$(LIBSOREL)
-	(cd $(DL); \
-	$(LN_SF) $(LIBSOREL) $(LIBSO); \
-	$(LN_SF) $(LIBSO) $(OLDSO))
-	-@if [ ! -d $(DL)/pkgconfig ]; then $(MKDIR_P) $(DL)/pkgconfig; fi
-	-@$(RM_F) $(DL)/pkgconfig/$(LIBNAME).pc
-	-@$(RM_F) $(DL)/pkgconfig/libpng.pc
-	cp libpng.pc $(DL)/pkgconfig/$(LIBNAME).pc
-	chmod 644 $(DL)/pkgconfig/$(LIBNAME).pc
-	(cd $(DL)/pkgconfig; $(LN_SF) $(LIBNAME).pc libpng.pc)
-
-install-man: libpng.3 libpngpf.3 png.5
-	-@if [ ! -d $(DM) ]; then $(MKDIR_P) $(DM); fi
-	-@if [ ! -d $(DM)/man3 ]; then $(MKDIR_P) $(DM)/man3; fi
-	-@$(RM_F) $(DM)/man3/libpng.3
-	-@$(RM_F) $(DM)/man3/libpngpf.3
-	cp libpng.3 $(DM)/man3
-	cp libpngpf.3 $(DM)/man3
-	-@if [ ! -d $(DM)/man5 ]; then $(MKDIR_P) $(DM)/man5; fi
-	-@$(RM_F) $(DM)/man5/png.5
-	cp png.5 $(DM)/man5
-
-install-config: libpng-config
-	-@if [ ! -d $(DB) ]; then $(MKDIR_P) $(DB); fi
-	-@$(RM_F) $(DB)/libpng-config
-	-@$(RM_F) $(DB)/$(LIBNAME)-config
-	cp libpng-config $(DB)/$(LIBNAME)-config
-	chmod 755 $(DB)/$(LIBNAME)-config
-	(cd $(DB); $(LN_SF) $(LIBNAME)-config libpng-config)
-
-install: install-static install-shared install-man install-config
-
-# If you installed in $(DESTDIR), test-installed won't work until you
-# move the library to its final location.  Use test-dd to test it
-# before then.
-
-test-dd:
-	echo
-	echo Testing installed dynamic shared library in $(DL).
-	$(CC) -I$(DI) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(DL) -L$(ZLIBLIB) -Wl, -rpath,$(DL) -Wl,-rpath,$(ZLIBLIB) \
-	   -o pngtestd `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtestd pngtest.png
-
-test-installed:
-	$(CC) -I$(ZLIBINC) \
-	   `$(BINPATH)/$(LIBNAME)-config --cflags` pngtest.c \
-	   -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \
-	   -o pngtesti `$(BINPATH)/$(LIBNAME)-config --ldflags`
-	./pngtesti pngtest.png
-
-clean:
-	$(RM_F) *.o libpng.a libpng.syms pngtest pngout.png libpng-config \
-	$(LIBSO) $(LIBSOMAJ)* pngtest-static pngtesti \
-	libpng.pc pnglibconf.h
-
-DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
-writelock:
-	chmod a-w *.[ch35] $(DOCS) scripts/*
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o png.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrio.o pngrio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwio.o pngwio.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngmem.o pngmem.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngset.o pngset.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngget.o pngget.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngread.o pngread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
-
-pngtest.o: png.h pngconf.h pnglibconf.h
--- a/scripts/makefile.freebsd
+++ b/scripts/makefile.freebsd
@@ -1,4 +1,5 @@
 # makefile for libpng under FreeBSD
+# Copyright (C) 2014 Glenn Randers-Pehrson and Andrey A. Chernov
 # Copyright (C) 2002, 2007, 2009 Glenn Randers-Pehrson and Andrey A. Chernov
 #
 # This code is released under the libpng license.
@@ -12,12 +13,12 @@ LIB=		png
 SHLIB_MAJOR=	${SHLIB_VER}
 SHLIB_MINOR=	0
 NO_PROFILE=	YES
-NO_OBJ=          YES
+NO_OBJ=		YES

 # where make install puts libpng.a and png.h
 DESTDIR=	${PREFIX}
 LIBDIR=		/lib
-INCS=		png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h             pnginfo.h pngdebug.h
+INCS=		png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 INCSDIR=	/include/libpng
 INCDIR=		${INCSDIR}		# for 4.x bsd.lib.mk
 MAN=		libpng.3 libpngpf.3 png.5
@@ -30,17 +31,25 @@ SYMLINKS=       libpng/png.h ${INCSDIR}/../png.h \
 ZLIBLIB=	/usr/lib
 ZLIBINC=	/usr/include

-LDADD+=        -lm -lz
-#LDADD+=       -lm -lz -lssp_nonshared   # for OSVERSION < 800000 ?
+LDADD+=		-lm -lz
+#LDADD+=	-lm -lz -lssp_nonshared   # for OSVERSION < 800000 ?

-DPADD+=         ${LIBM} ${LIBZ}
+DPADD+=		${LIBM} ${LIBZ}

-CFLAGS+= -I. -I${ZLIBINC}
+CPPFLAGS+=	-I. -I${ZLIBINC}
+CFLAGS+=	-W -Wall
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt

 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c

+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
 pngtest: pngtest.o libpng.a
 	${CC} ${CFLAGS} -L. -static -o pngtest pngtest.o -L${ZLIBLIB} \
 	-lpng ${LDADD}
@@ -50,9 +59,8 @@ CLEANFILES= pngtest pngtest.o pngout.png
 test: pngtest
 	./pngtest

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	cp $(PNGLIBCONF_H_PREBUILT) $@

 DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
 writelock:
--- a/Show More
+++ b/Show More