[libpng16] Imported from libpng-1.6.11beta02.tar

[libpng16] Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that
interferes with "blocky" expansion of sub-8-bit interlaced PNG files.
2025-07-10 18:04:09 +02:00 · 2014-04-06 09:07:56 -05:00 · 2014-04-06 09:06:37 -05:00 · 2014-03-25 17:10:53 -05:00 · 2014-03-25 17:10:44 -05:00 · 2014-03-22 18:44:24 -05:00
98 changed files with 3054 additions and 4318 deletions
--- a/576
+++ b/576
@@ -1,5 +1,5 @@

-Libpng 1.7.0beta34 - March 17, 2014
+Libpng 1.6.11beta02 - April 6, 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.
@@ -9,569 +9,42 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script

-   1.7.0beta34.tar.xz (LZMA-compressed, recommended)
-   1.7.0beta34.tar.gz
+   1.6.11beta02.tar.xz (LZMA-compressed, recommended)
+   1.6.11beta02.tar.gz

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

-   lp170b34.7z  (LZMA-compressed, recommended)
-   lp170b34.zip
+   lp1611b02.7z  (LZMA-compressed, recommended)
+   lp1611b02.zip

 Other information:

-   1.7.0beta34-README.txt
-   1.7.0beta34-LICENSE.txt
-   libpng-1.7.0beta34-*.asc (armored detached GPG signatures)
+   1.6.11beta02-README.txt
+   1.6.11beta02-LICENSE.txt
+   libpng-1.6.11beta02-*.asc (armored detached GPG signatures)

-Changes since the last public release (1.6.0):
+Changes since the last public release (1.6.10):

-Version 1.7.0alpha01 [December 15, 2012]
-  Started 1.7.0 branch from libpng-1.6.0beta33.
-  Made 8-bit compose and rgb_to_grayscale accuracy improvements.  These
-    changes cause 16-bit arithmetic to be used for 8-bit data in the gamma
-    corrected compose and grayscale operations.  The arithmetic errors have
-    three sources all of which are fixed in this commit:
-    1) 8-bit linear calculations produce massive errors for lower intensity
-       values.
-    2) The old 16-bit "16 to 8" gamma table code erroneously wrote the lowest
-       output value into a table entry which corresponded to multiple output
-       values (so where the value written should have been the closest to the
-       transformed input value.)
-    3) In a number of cases the code to access the 16-bit table did not round;
-       it did a simple shift, which was wrong and made the side effects of (2)
-       even worse.
-  The new gamma code does not have the 16-to-8 problem at the cost of slightly
-    more calculations and the algorithm used to minimize the number of
-    calculations has been extended to all the 16-bit tables; it has advantages
-    for any significant gamma correction.
-  Rearranged png_struct, remove unused members, change png_set_filter handling
-    png_struct members rearranged - partly to reorder to avoid packing, partly
-    to put frequently accessed members at the start and partly to make
-    the grouping more clear. png_set_filter code has been rewritten and the
-    code shared with png_write_start_row moved to a common function.  Comments
-    in png.h have been made more clear. Minor fixes to
-    contrib/libtests/timepng.c and some of the png_*_tRNS logic, including
-    more error detection in png_set_tRNS.
-  Cleaned up USER_LIMITS feature, removing members from png_struct when not
-    required.
-  Rearranged ARM-NEON optimizations to isolate the machine specific code to
-    the hardware subdirectory, and add comments to pngrutil.c so that
-    implementors of other optimizations will know what to do.
-  Fixed cases of unquoted DESTDIR in Makefile.am.
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.12.5.
-
-Version 1.7.0alpha02 [December 17, 2012]
-  Removed functions that were deprecated in libpng-1.6.0:
-    png_reset_zstream(), png_info_init_3(), and png_data_freer() and its
-    associated flags.
-  Removed some duplicated lines from contrib/tools/scale.c and png.c.
-  Changed some instances of png_warning() to png_app_error().
-  Updated some left over "1.6.0beta32" in code sources.
-  Fixed a "png_structp" prototype (should be png_structrp) in arm_init.c
-  Updated the version-number hack in pngvalid.c
-
-Version 1.7.0alpha03 [December 19, 2012]
-  Cleaned up and enhanced the configure option; libpng now correctly
-    links and tests against zlib with a prefix; tests have been clarified; and
-    irrelevant or obsolete things (as defined by the autotools man page) have
-    been removed.
-  Documented new PNG_ABORT behavior in the manual and commentary in pngerror.c
-  Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
-  Fixed previous support for Z_PREFIX in configure builds, corrected sCAL APIs;
-    some of these use floating point arithmetic so they need to be disabled if
-    floating point arithmetic is switched off.  This is a quiet API change -
-    previously it appeared that the APIs were supported if fixed point
-    arithmetic was used internally, however they required certain APIs (floor,
-    modf, frexp, atof) that are part of C floating point support. Changed
-    png_fixed and the gamma code specific version of the same to avoid floor(),
-    which may be a library function (not an intrinsic). Removed unused #if 0
-    code.
-  Disassembled the version number in scripts/options.awk (necessary for
-    building on SunOs).
-
-Version 1.7.0alpha04 [December 23, 2012]
-  Added scripts/makefile.msys contributed by Christopher M. Wheeler
-  Made default Zlib compression settings be configurable. This adds #defines to
-    pnglibconf.h to control the defaults.
-  Fixed Windows build issues, enabled ARM compilation. Various warnings issued
-    by earlier versions of GCC fixed for Cygwin and Min/GW (which both use old
-    GCCs.) ARM support is enabled by default in zlib.props (unsupported by
-    Microsoft) and ARM compilation is made possible by deleting the check for
-    x86. The test programs cannot be run because they are not signed.
-
-Version 1.7.0alpha05 [December 24, 2012]
-  Discontinued distributing libpng-1.x.x.tar.bz2.
-  Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar.
-
-Version 1.7.0alpha06 [January 1, 2013]
-  Fixed 'make distcheck' on SUN OS - libpng.so was not being removed
-
-Version 1.7.0alpha07 [January 10, 2013]
-  Fixed conceivable but difficult to repro overflow. Also added two test
-    programs to generate and test a PNG which should have the problem.
-
-Version 1.7.0alpha08 [January 17, 2013]
-  Corrected previous attempt at overflow detection in png_set_unknown_chunks().
-
-Version 1.7.0alpha09 [January 21, 2013]
-  Pulled changes to multi-chunk handling from libpng-1.6.0beta40.
-
-Version 1.7.0alpha10 [February 5, 2013]
-  Make symbol prefixing work with the ARM neon optimizations. Also
-    allow pngpriv.h to be included for preprocessor definitions only, so
-    it can be used in non-C/C++ files.
-  Added png_get_palette_max() function.
-  Changed png_size_t to size_t throughout headers, make sRGB check numbers
-    consistent.
-  Fixed ARM support (Mans Rullgard).
-  Removed stray out-of-order #endif and #ifdef (Mans Rullgard).
-  Ported libpng 1.5 options.awk/dfn file handling to 1.7, fixed one bug.
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.13.
-  Minor fixes to assembler changes, verified with a dummy .S file
-  Removed cc -E workround, corrected png_get_palette_max API. Tested on
-    SUN OS cc 5.9, which demonstrates the tokenization problem previously
-    avoided by using /lib/cpp.  Since all .dfn output is now protected
-    in double quotes unless it is to be macro substituted the fix should work
-    everywhere.
-
-Version 1.7.0beta01 [February 15, 2013]
-  Enable parallel tests and rearrange TESTS order to take advantage of
-    the massive speed improvements use a make capable of parallel builds
-    on a multi-CPU machine and pass the right arguments to make (-j10000
-    for GNU make) to get the build to run in parallel.
-  Fixed previous support for Z_PREFIX in configure builds, corrected
-    sCAL APIs; some of these use floating point arithmetic so need to be
-    disabled if floating point arithmetic is switched off.  This is a quiet API
-    change - previously it appeared that the APIs were supported if fixed point
-    arithmetic was used internally, however they required certain APIs (floor,
-    modf, frexp, atof) that are part of C floating point support. Changed
-    png_fixed and the gamma code specific version of the same to avoid floor(),
-    which may be a library function (not an intrinsic). Removed unused #if 0
-    code.
-  Fixed make distcheck to skip over the test result files. They were
-    being included because the whole of the 'tests' directory is included,
-    fixed to just include the actual test files and tests/pngstest.  Also
-    reverted the previous erroneous change to remove the ${srcdir} from the
-    front of contrib, scripts, projects and added an explanation of what is
-    going on to Makefile.am
-  Fixed missing dependency in --prefix builds. The intermediate
-    internal 'prefix.h' file can only be generated correctly after pnglibconf.h,
-    however the dependency was not in Makefile.am.  The symptoms are
-    unpredictable depending on the order make chooses to build pngprefix.h and
-    pnglibconf.h, often the error goes unnoticed because there is a system
-    pnglibconf.h to use instead.
-  Accept "," as a separator in pnglibconf.dfa and allow for
-    continuation lines. This adds to the syntax of "option" and "chunk" lines,
-    allowing the elements to be separated by a "," at the end of an element and
-    interpreting a "," at end of line as a continuation - so the following line
-    is read.  The new syntax is optional and solely provided for readability.
-  Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED
-    block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly.
-
-Version 1.7.0beta02 [February 18, 2013]
-  Fixed a race condition in the creation of the build 'scripts' directory
-    while building with a parallel make.
-  Use approved/supported Android method to check for NEON, use Linux/POSIX
-    1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
-    library calls (ported from libpng15).
-  Use parentheses more consistently in "#if defined(MACRO)" tests.
-  Folded long lines.
-
-Version 1.7.0beta03 [February 22, 2013]
-  Reenabled code to allow zero length PLTE chunks for MNG.
-  Fixed ALIGNED_MEMORY support.
-  Allow run-time ARM NEON checking to be disabled. A new configure option:
-    --enable-arm-neon=always will stop the run-time checks. New checks
-    within arm/arm_init.c will cause the code not to be compiled unless
-    __ARM_NEON__ is set. This should make it fail safe (if someone asks
-    for it on then the build will fail if it can't be done.)
-  Updated the INSTALL document.
-
-Version 1.7.0beta04 [February 27, 2013]
-  Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES.
-  Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC.
-  Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble
-    with CRLF line endings.
-
-Version 1.7.0beta05 [March 5, 2013]
-  Avoid a possible memory leak in contrib/gregbook/readpng.c
-  Changed user chunk callback API to respect global and per chunk defaults.
-    Previously a return of 0 from a user chunk callback would result in the
-    chunk being saved (if this was safe, even if the chunk was unsafe-to-copy);
-    this change respects the defaults set by the application, so unknown chunks
-    can be discarded by default and known-safe ones preserved.
-  Corrected Android builds and corrected libpng.vers with symbol
-    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.  The order of settings vs options in
-    pnglibconf.h is reversed to allow settings to depend on options and
-    options can now set (or override) the defaults for settings.
-
-Version 1.7.0beta06 [March 13, 2013]
-  Corrected simplified API default gamma for color-mapped output, added
-    a flag to change default. In 1.6.0 when the simplified API was used
-    to produce color-mapped output from an input image with no gamma
-    information the gamma assumed for the input could be different from
-    that assumed for non-color-mapped output.  In particular 16-bit depth
-    input files were assumed to be sRGB encoded, whereas in the 'direct'
-    case they were assumed to have linear data.  This was an error.  The
-    fix makes the simplified API treat all input files the same way and
-    adds a new flag to the png_image::flags member to allow the
-    application/user to specify that 16-bit files contain sRGB data
-    rather than the default linear.
-  Fixed bugs in the pngpixel and makepng test programs.
-  Fixed CMakelists.txt to allow building a single variant of the library
-    (Claudio Bley):
-  Introduced a PNG_LIB_TARGETS variable that lists all activated library
-    targets.  It is an error if this variable ends up empty, ie. you have
-    to build at least one library variant.
-  Made the *_COPY targets only depend on library targets actually being build.
-  Use PNG_LIB_TARGETS to unify a code path.
-  Changed the CREATE_SYMLINK macro to expect the full path to a file as the
-    first argument. When symlinking the filename component of that path is
-    determined and used as the link target.
-  Use copy_if_different in the CREATE_SYMLINK macro.
-  Eliminated two warnings from the Intel C compiler. The warnings are
-    technically valid, although a reasonable treatment of division would
-    show it to be incorrect.
-
-Version 1.7.0beta07 [April 14, 2013]
-  Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling.
-  Fixed incorrect warning of excess deflate data. End condition - the
-    warning would be produced if the end of the deflate stream wasn't read
-    in the last row.  The warning is harmless.
-  Corrected the test on user transform changes on read. It was in the
-    png_set of the transform function, but that doesn't matter unless the
-    transform function changes the rowbuf size, and that is only valid if
-    transform_info is called.
-  Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c
-    (Flavio Medeiros).
-  Corrected length written to uncompressed iTXt chunks (Samuli Suominen).
-
-Version 1.7.0beta08 [April 18, 2013]
-  Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length
-    written by libpng-1.6.0 and 1.6.1.
-  Disallow storing sRGB information when the sRGB is not supported.
-
-Version 1.7.0beta09 [April 24, 2013]
-  Exposed PNG chunk types in png.h
-  Modified png_uint_32 macros/code to make as few assumptions as possible
-  Revised stack marking in arm/filter_neon.S and configure.ac
-  Ensure that NEON filter stuff is completely disabled when switched 'off'.
-    Previously the ARM NEON specific files were still built if the option
-    was switched 'off' as opposed to being explicitly disabled.
-
-Version 1.7.0beta10 [April 24, 2013]
-  Attempt to fix the PNG_ARM_NEON configuration mess.
-
-Version 1.7.0beta11 [April 26, 2013]
-  Test for 'arm*', not just 'arm' in the host_cpu configure variable.
-
-Version 1.7.0beta12 [April 30, 2013]
-  Added png_app_warning for out-of-range unknown chunk index in
-    png_set_unknown_chunk_location().
-  Expanded manual paragraph about writing private chunks.
-  Avoid dereferencing NULL pointer possibly returned from
-     png_create_write_struct() (Andrew Church).
-
-Version 1.7.0beta13 [May 12, 2013]
-  Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
-    right zlib header files.
-  Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
-  Updated contrib/pngminus/pnm2png.c (Paul Stewart):
-    Check for EOF
-    Ignore "#" delimited comments in input file to pnm2png.c.
-    Fixed whitespace handling
-    Added a call to png_set_packing()
-    Initialize dimension values so if sscanf fails at least we have known
-      invalid values.
-  Calculate our own zlib windowBits when decoding rather than trusting the
-    CMF bytes in the PNG datastream.
-  Added an option to force maximum window size for inflating, which was
-    the behavior of libpng15 and earlier.
-  Added png-fix-itxt and png-fix-too-far-back to the built programs and
-    removed warnings from the source code and timepng that are revealed as
-    a result.
-  Detect wrong libpng versions linked to png-fix-too-far-back, which currently
-    only works with libpng versions that can be made to reliably fail when
-    the deflate data contains an out-of-window reference.  This means only
-    1.6 and later.
-  Attempt to detect configuration issues with png-fix-too-far-back, which
-    requires both the correct libpng and the correct zlib to function
-    correctly.
-  Check ZLIB_VERNUM for mismatches, enclose #error in quotes
-  Added information in the documentation about problems with and fixes for
-    the bad CRC and bad iTXt chunk situations.
-
-Version 1.7.0beta14 [June 8, 2013]
-  Removed a redundant test in png_set_IHDR().
-  Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt)
-  Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
-  Enclose the prototypes for the simplified write API in #ifdef STDIO/#endif
-  Make ARM NEON support work at compile time (not just configure time).
-    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
-    using a compiler that compiles for multiple architectures at one time.
-  Removed PNG_FILTER_OPTIMIZATIONS and PNG_ARM_NEON_SUPPORTED from
-    pnglibconf.h, allowing more of the decisions to be made internally
-    (pngpriv.h) during the compile.  Without this, symbol prefixing is broken
-    under certain circumstances on ARM platforms.  Now only the API parts of
-    the optimizations ('check' vs 'api') are exposed in the public header files
-    except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the
-    decision about whether or not to use the optimizations.
-  Protect symbol prefixing against CC/CPPFLAGS/CFLAGS useage.
-    Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test
-    on __ARM_NEON__ from configure time to compile time.  This breaks symbol
-    prefixing because the definition of the special png_init_filter_functions
-    call was hidden at configure time if the relevant compiler arguments are
-    passed in CFLAGS as opposed to CC.  This change attempts to avoid all
-    the confusion that would result by declaring the init function even when
-    it is not used, so that it will always get prefixed.
-
-Version 1.7.0beta15 [June 18, 2013]
-  Revised libpng.3 so that "doclifter" can process it.
-
-Version 1.7.0beta16 [July 5, 2013]
-  Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
-    as parameters for png_set_gamma().  These have been available since
-    libpng-1.5.4.
-  Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
-    to check all compressed chunks known to libpng.
-  Updated documentation to show default behavior of benign errors correctly.
-  Added perfect hash code generation for lists of PNG chunks. This is
-    a work in progress; checked in for use in pngfix.c
-  Ported ARM no-read patch from libpng16.
-  Ported pngfix.c patches from libpng16.
-
-Version 1.7.0beta17 [August 21, 2013]
-  Revised manual about changes in iTXt chunk handling made in libpng-1.6.0.
-  Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings
-    may be erroneously issued by code-checking applications.
-  Added information about png_set_options() to the manual.
-  Delay calling png_init_filter_functions() until a row with nonzero filter
-    is found.
-
-Version 1.7.0beta18 [September 16, 2013]
-  Fixed inconsistent conditional compilation of png_chunk_unknown_handling()
-    prototype, definition, and usage.  Made it depend on
-    PNG_HANDLE_AS_UNKNOWN_SUPPORTED everywhere.
-
-Version 1.7.0beta19 [September 30, 2013]
-  Reverted the change to unknown handling #defines; the change breaks 'NOREAD'
-    builds.
-  Fixed default behavior of ARM_NEON_API. If the ARM NEON API option is
-    compiled without the CHECK option it defaulted to on, not off.
-  Catch up with recent libpng16 changes; unknown handling and spelling
-    corrections
-  Avoid up-cast warnings in pngvalid.c. On ARM the alignment requirements of
-    png_modifier are greater than that of png_store and as a consequence
-    compilation of pngvalid.c results in a warning about increased alignment
-    requirements because of the bare cast to (png_modifier*).  The code is
-    safe, because the pointer is known to point to a stack allocated
-    png_modifier, but this change avoids the warning.
-  Fixed some grammatical changes and updated the png chunks list.
-
-Version 1.7.0beta20 [October 13, 2013]
-  Made changes for compatibility with automake 1.14:
-    1) Added the 'compile' program to the list of programs that must be cleaned
-       in autogen.sh
-    2) Added 'subdir-objects' which causes .c files in sub-directories to be
-       compiled such that the corresponding .o files are also in the
-       sub-directory.  This is because automake 1.14 warns that the
-       current behavior of compiling to the top level directory may be removed
-       in the future.
-    3) Updated dependencies on pnglibconf.h to match the new .o locations and
-       added all the files in contrib/libtests and contrib/tools that depend
-       on pnglibconf.h
-    4) Added 'BUILD_SOURCES = pnglibconf.h'; this is the automake recommended
-       way of handling the dependencies of sources that are machine generated;
-       unfortunately it only works if the user does 'make all' or 'make check',
-       so the dependencies (3) are still required.
-  Cleaned up (char*) casts of zlib messages. The latest version of the Intel C
-    compiler complains about casting a string literal as (char*), so copied the
-    treatment of z_const from the library code into pngfix.c
-  Simplified error message code in pngunknown. The simplification has the
-    useful side effect of avoiding a bogus warning generated by the latest
-    version of the Intel C compiler (it objects to
-    condition ? string-literal : string-literal).
-  Make autogen.sh work with automake 1.13 as well as 1.14. Do this by always
-    removing the 1.14 'compile' script but never checking for it.
-
-Version 1.7.0beta21 [November 2, 2013]
-  Added ARMv8 support (James Yu <james.yu at linaro.org>).  Added file
-    arm/filter_neon_intrinsics.c; enable with -mfpu=neon.
-  Revised pngvalid to generate size images with as many filters as it can
-    manage, limited by the number of rows.
-  Cleaned up ARM NEON compilation handling. The tests are now in pngpriv.h
-    and detect the broken GCC compilers.
-  Allow clang derived from older GCC versions to use ARM intrinsics. This
-    causes all clang builds that use -mfpu=neon to use the intrinsics code,
-    not the assembler code.  This has only been tested on iOS 7. It may be
-    necessary to exclude some earlier clang versions but this seems unlikely.
-  Changed NEON implementation selection mechanism. This allows assembler
-    or intrinsics to be turned on at compile time during the build by defining
-    PNG_ARM_NEON_IMPLEMENTATION to the correct value (2 or 1).  This macro
-    is undefined by default and the build type is selected in pngpriv.h.
-
-Version 1.7.0beta22 [November 7, 2013]
-  Fixed #include in filter_neon_intrinsics.c and ctype macros. The ctype char
-    checking macros take an unsigned char argument, not a signed char.
-
-Version 1.7.0beta23 [November 24, 2013]
-  Changed #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED in pngpread.c to
-    #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED to be consistent with
-    what is in pngpriv.h.
-  Moved prototype for png_handle_unknown() in pngpriv.h outside of
-    the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
-  Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
-  Conditionally compile some unused functions reported by -Wall in
-    pngminim.
-  Fixed 'minimal' builds. Various obviously useful minimal configurations
-    don't build because of missing contrib/libtests test programs and
-    overly complex dependencies in scripts/pnglibconf.dfa. This change
-    adds contrib/conftest/*.dfa files that can be used in automatic build
-    scripts to ensure that these configurations continue to build.
-  Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder.
-  Fixed pngvalid 'fail' function declaration on the Intel C Compiler.
-    This reverts to the previous 'static' implementation and works round
-    the 'unused static function' warning by using PNG_UNUSED().
-
-Version 1.7.0beta24 [December 15, 2013]
-  Removed or marked PNG_UNUSED some harmless "dead assignments" reported
-    by clang scan-build.
-  Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
-    to '"%s" m' to improve portability among compilers.
-  Changed png_free_default() to free() in pngtest.c
-  Tidied up pngfix inits and fixed pngtest no-write builds.
-  Bookkeeping: Moved functions around (no changes). Moved transform
-    function definitions before the place where they are called so that
-    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
-  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.
-  Handle zero-length PLTE chunk or NULL palette with png_error()
-    instead of png_chunk_report(), which by default issues a warning
-    rather than an error, leading to later reading from a NULL pointer
-    (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
-    and VU#650142.  Libpng-1.6.1 through 1.6.7 and libpng-1.7.0beta03
-    through 1.7.0beta23 are vulnerable.  Libpng-1.6.0 and earlier do not
-    have the bug.
-
-Version 1.7.0beta25 [December 26, 2013]
-  Merged files with version 1.6.8 that have not changed since then.
-  Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69
-
-Version 1.7.0beta26 [January 1, 2014]
-  Added libpng 1.5 checks to pngvalid.c
-  Merged with 1.5 and 1.6 changes to create a single pngvalid.c
-  Added dSIG to chunk list in png.h
-  Removed #error macro from contrib/tools/pngfix.c (Thomas Klausner).
-  Merged pngrio.c, pngtrans.c, and pngwio.c with libpng-1.6.9
-  Fixed test programs for interlace options. Made pngvalid.c and
-    pngtest.c work correctly when READ_INTERLACING and/or WRITE_INTERLACING
-    are switched off.
-  Changed 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.
-
-Version 1.7.0beta27 [January 10, 2014]
-  Removed potentially misleading warning from png_check_IHDR().
-
-Version 1.7.0beta28 [January 20, 2014]
-  Updated scripts/makefile.* to use CPPFLAGS (Cosmin).
-  Added clang attribute support (Cosmin).
-
-Version 1.7.0beta29 [January 30, 2014]
-  Quiet an uninitialized memory warning from VS2013 in png_get_png().
-
-Version 1.7.0beta30 [February 2, 2014]
-  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. This
-    is a work-in-progress; no tests are run automatically at present and
-    the program by virtue of exhaustively testing all the transforms is
-    very slow.
-
-Version 1.7.0beta31 [February 6, 2014]
-  Make png_read_png() and png_write_png() prototypes in png.h depend
-    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
-  Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling
-    png_set_packing() in png_read_png().
-  Completed full working pngimage test program and added two test scripts.
-  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).
-  Restored a line, "c = b;", that was inadvertently deleted from the
-    PAETH filtering code from libpng-1.7.0beta24/pngrutil.c. Deleted
-    the other instance of "c = b;" which is the one that triggered a
-    scan-build warning.
-  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 1.7.0beta32 [February 26, 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).
-  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.
-  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
-  Moved some documentation from png.h to libpng.3 and libpng-manual.txt
-
-Version 1.7.0beta33 [February 27, 2014]
-  Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS
-    and PNG_USR_CONFIG -> PNG_USER_CONFIG).
-
-Version 1.7.0beta34 [March 17, 2014]
-  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.
+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).
+  $(CP) is now used alongside $(RM_F).  Also, use 'copy' instead
+    of 'cp' where applicable, and applied other minor makefile changes.
+  Don't warn about invalid dimensions exceeding user limits.
+  Allow an easy replacement of the default pre-built configuration
+    header with a custom header, via the make PNGLIBCONF_H_PREBUILT
+    macro.
+  Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes
+    with "blocky" expansion of sub-8-bit interlaced PNG files.
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
@@ -579,3 +52,4 @@ to subscribe)
 or to glennrp at users.sourceforge.net

 Glenn R-P
+#endif
--- a/505
+++ b/505
@@ -3780,7 +3780,8 @@ Version 1.5.7 [December 15, 2011]

 Version 1.6.0beta01 [December 15, 2011]
  Removed machine-generated configure files from the GIT repository (they will
-    continue to appear in the tarball distributions).
+    continue to appear in the tarball distributions and in the libpng15 and
+    earlier GIT branches).
  Restored the new 'simplified' API, which was started in libpng-1.5.7beta02
    but later deleted from libpng-1.5.7beta05.
  Added example programs for the new 'simplified' API.
@@ -4307,79 +4308,24 @@ Version 1.6.0beta32 [November 25, 2012]
  Fixed error checking in the simplified write API (Olaf van der Spek)
  Made png_user_version_check() ok to use with libpng version 1.10.x and later.

-Version 1.6.0beta33 [December 10, 2012]
+Version 1.6.0beta33 [December 15, 2012]
  Fixed typo in png.c (PNG_SET_CHUNK_MALLOC_MAX should be PNG_CHUNK_MALLOC_MAX)
    that causes the MALLOC_MAX limit not to work (John Bowler)
  Change png_warning() to png_app_error() in pngwrite.c and comment the
    fall-through condition.
  Change png_warning() to png_app_warning() in png_write_tRNS().
+  Rearranged the ARM-NEON optimizations: Isolated the machine specific code
+    to the hardware subdirectory and added comments to pngrutil.c so that
+    implementors of other optimizations know what to do.
+  Fixed cases of unquoted DESTDIR in Makefile.am
+  Rebuilt Makefile.in, etc., with autoconf-2.69 and automake-1.12.5.

-Version 1.7.0alpha01 [December 15, 2012]
-  Started 1.7.0 branch from libpng-1.6.0beta33.
-  Made 8-bit compose and rgb_to_grayscale accuracy improvements.  These
-    changes cause 16-bit arithmetic to be used for 8-bit data in the gamma
-    corrected compose and grayscale operations.  The arithmetic errors have
-    three sources all of which are fixed in this commit:
-    1) 8-bit linear calculations produce massive errors for lower intensity
-       values.
-    2) The old 16-bit "16 to 8" gamma table code erroneously wrote the lowest
-       output value into a table entry which corresponded to multiple output
-       values (so where the value written should have been the closest to the
-       transformed input value.)
-    3) In a number of cases the code to access the 16-bit table did not round;
-       it did a simple shift, which was wrong and made the side effects of (2)
-       even worse.
-  The new gamma code does not have the 16-to-8 problem at the cost of slightly
-    more calculations and the algorithm used to minimize the number of
-    calculations has been extended to all the 16-bit tables; it has advantages
-    for any significant gamma correction.
-  Rearranged png_struct, remove unused members, change png_set_filter handling
-    png_struct members rearranged - partly to reorder to avoid packing, partly
-    to put frequently accessed members at the start and partly to make
-    the grouping more clear. png_set_filter code has been rewritten and the
-    code shared with png_write_start_row moved to a common function.  Comments
-    in png.h have been made more clear. Minor fixes to
-    contrib/libtests/timepng.c and some of the png_*_tRNS logic, including
-    more error detection in png_set_tRNS.
-  Cleaned up USER_LIMITS feature, removing members from png_struct when not
-    required.
-  Rearranged ARM-NEON optimizations to isolate the machine specific code to
-    the hardware subdirectory, and add comments to pngrutil.c so that
-    implementors of other optimizations will know what to do.
-  Fixed cases of unquoted DESTDIR in Makefile.am.
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.12.5.
-
-Version 1.7.0alpha02 [December 17, 2012]
-  Removed functions that were deprecated in libpng-1.6.0:
-    png_reset_zstream(), png_info_init_3(), png_data_freer() and its
-    associated flags, png_malloc_default, and png_free_default.
-  Removed some duplicated lines from contrib/tools/scale.c and png.c.
-  Changed some instances of png_warning() to png_app_error().
-  Updated some left over "1.6.0beta32" in code sources.
-  Fixed a "png_structp" prototype (should be png_structrp) in arm_init.c
-  Updated the version-number hack in pngvalid.c
-  
-Version 1.7.0alpha03 [December 19, 2012]
-  Cleaned up and enhanced the configure option; libpng now correctly
-    links and tests against zlib with a prefix; tests have been clarified; and
-    irrelevant or obsolete things (as defined by the autotools man page) have
-    been removed.
-  Documented new PNG_ABORT behavior in the manual and commentary in pngerror.c
+Version 1.6.0beta34 [December 19, 2012]
  Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
-  Fixed previous support for Z_PREFIX in configure builds, corrected sCAL APIs;
-    some of these use floating point arithmetic so they need to be disabled if
-    floating point arithmetic is switched off.  This is a quiet API change -
-    previously it appeared that the APIs were supported if fixed point
-    arithmetic was used internally, however they required certain APIs (floor,
-    modf, frexp, atof) that are part of C floating point support. Changed
-    png_fixed and the gamma code specific version of the same to avoid floor(),
-    which may be a library function (not an intrinsic). Removed unused #if 0
-    code.
  Disassembled the version number in scripts/options.awk (necessary for
    building on SunOs).

-Version 1.7.0alpha04 [December 23, 2012]
-  Added scripts/makefile.msys contributed by Christopher M. Wheeler
+Version 1.6.0beta35 [December 23, 2012]
  Made default Zlib compression settings be configurable. This adds #defines to
    pnglibconf.h to control the defaults.
  Fixed Windows build issues, enabled ARM compilation. Various warnings issued
@@ -4388,86 +4334,81 @@ Version 1.7.0alpha04 [December 23, 2012]
    Microsoft) and ARM compilation is made possible by deleting the check for
    x86. The test programs cannot be run because they are not signed.

-Version 1.7.0alpha05 [December 24, 2012]
+Version 1.6.0beta36 [January 2, 2013]
  Discontinued distributing libpng-1.x.x.tar.bz2.
  Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar.
-
-Version 1.7.0alpha06 [January 1, 2013]
+  Rebuilt configure with autoconf-2.69 (inadvertently not done in beta33)
  Fixed 'make distcheck' on SUN OS - libpng.so was not being removed

-Version 1.7.0alpha07 [January 10, 2013]
+Version 1.6.0beta37 [January 10, 2013]
  Fixed conceivable but difficult to repro overflow. Also added two test
    programs to generate and test a PNG which should have the problem.

-Version 1.7.0alpha08 [January 17, 2013]
-  Corrected previous attempt at overflow detection in png_set_unknown_chunks().
+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().

-Version 1.7.0alpha09 [January 21, 2013]
-  Pulled changes to multi-chunk handling from libpng-1.6.0beta40.
+Version 1.6.0beta40 [January 20, 2013]
+  Use consistent handling of overflows in text, sPLT and unknown png_set_* APIs

-Version 1.7.0alpha10 [February 5, 2013]
-  Make symbol prefixing work with the ARM neon optimizations. Also
-    allow pngpriv.h to be included for preprocessor definitions only, so
-    it can be used in non-C/C++ files.
+Version 1.6.0rc01 [January 26, 2013]
+  No changes.
+
+Version 1.6.0rc02 [February 4, 2013]
  Added png_get_palette_max() function.
-  Changed png_size_t to size_t throughout headers, make sRGB check numbers
-    consistent.
-  Fixed ARM support (Mans Rullgard).
-  Removed stray out-of-order #endif and #ifdef (Mans Rullgard).
-  Ported libpng 1.5 options.awk/dfn file handling to 1.7, fixed one bug.
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.13.
-  Minor fixes to assembler changes, verified with a dummy .S file
-  Removed cc -E workround, corrected png_get_palette_max API. Tested on
-    SUN OS cc 5.9, which demonstrates the tokenization problem previously
-    avoided by using /lib/cpp.  Since all .dfn output is now protected
-    in double quotes unless it is to be macro substituted the fix should work
-    everywhere.

-Version 1.7.0beta01 [February 15, 2013]
-  Enable parallel tests and rearrange TESTS order to take advantage of
-    the massive speed improvements use a make capable of parallel builds
-    on a multi-CPU machine and pass the right arguments to make (-j10000
-    for GNU make) to get the build to run in parallel.
-  Fixed previous support for Z_PREFIX in configure builds, corrected
-    sCAL APIs; some of these use floating point arithmetic so need to be
-    disabled if floating point arithmetic is switched off.  This is a quiet API
-    change - previously it appeared that the APIs were supported if fixed point
-    arithmetic was used internally, however they required certain APIs (floor,
-    modf, frexp, atof) that are part of C floating point support. Changed
-    png_fixed and the gamma code specific version of the same to avoid floor(),
-    which may be a library function (not an intrinsic). Removed unused #if 0
-    code.
-  Fixed make distcheck to skip over the test result files. They were
-    being included because the whole of the 'tests' directory is included,
-    fixed to just include the actual test files and tests/pngstest.  Also
-    reverted the previous erroneous change to remove the ${srcdir} from the
-    front of contrib, scripts, projects and added an explanation of what is
-    going on to Makefile.am
-  Fixed missing dependency in --prefix builds. The intermediate
-    internal 'prefix.h' file can only be generated correctly after pnglibconf.h,
-    however the dependency was not in Makefile.am.  The symptoms are
-    unpredictable depending on the order make chooses to build pngprefix.h and
-    pnglibconf.h, often the error goes unnoticed because there is a system
-    pnglibconf.h to use instead.
-  Accept "," as a separator in pnglibconf.dfa and allow for
-    continuation lines. This adds to the syntax of "option" and "chunk" lines,
-    allowing the elements to be separated by a "," at the end of an element and
-    interpreting a "," at end of line as a continuation - so the following line
-    is read.  The new syntax is optional and solely provided for readability.
+Version 1.6.0rc03 [February 5, 2013]
+  Fixed the png_get_palette_max API.
+
+Version 1.6.0rc04 [February 7, 2013]
+  Turn serial tests back on (recently turned off by autotools upgrade).
+
+Version 1.6.0rc05 [February 8, 2013]
+  Update manual about png_get_palette_max().
+
+Version 1.6.0rc06 [February 9, 2013]
+  Fixed missing dependency in --prefix builds The intermediate
+    internal 'prefix.h' file can only be generated correctly after
+    pnglibconf.h, however the dependency was not in Makefile.am.  The
+    symptoms are unpredictable depending on the order make chooses to
+    build pngprefix.h and pnglibconf.h, often the error goes unnoticed
+    because there is a system pnglibconf.h to use instead.
+
+Version 1.6.0rc07 [February 10, 2013]
  Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED
    block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly.

-Version 1.7.0beta02 [February 18, 2013]
+Version 1.6.0rc08 [February 10, 2013]
+  Fix typo in png.h #ifdef
+
+Version 1.6.0 [February 14, 2013]
+  No changes.
+
+Version 1.6.1beta01 [February 16, 2013]
+  Made symbol prefixing work with the ARM neon optimizations. Also allow
+    pngpriv.h to be included for preprocessor definitions only, so it can
+    be used in non-C/C++ files. Back ported from libpng 1.7.
+  Made sRGB check numbers consistent.
+  Ported libpng 1.5 options.awk/dfn file handling to 1.6, fixed one bug.
+  Removed cc -E workround, corrected png_get_palette_max API Tested on
+    SUN OS cc 5.9, which demonstrates the tokenization problem previously
+    avoided by using /lib/cpp.  Since all .dfn output is now protected in
+    double quotes unless it is to be macro substituted the fix should
+    work everywhere.
+  Enabled parallel tests - back ported from libpng-1.7.
+  scripts/pnglibconf.dfa formatting improvements back ported from libpng17.
  Fixed a race condition in the creation of the build 'scripts' directory
    while building with a parallel make.
  Use approved/supported Android method to check for NEON, use Linux/POSIX
    1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
    library calls (ported from libpng15).
+
+Version 1.6.1beta02 [February 19, 2013]
  Use parentheses more consistently in "#if defined(MACRO)" tests.
  Folded long lines.
-
-Version 1.7.0beta03 [February 22, 2013]
  Reenabled code to allow zero length PLTE chunks for MNG.
+
+Version 1.6.1beta03 [February 22, 2013]
  Fixed ALIGNED_MEMORY support.
  Allow run-time ARM NEON checking to be disabled. A new configure option:
    --enable-arm-neon=always will stop the run-time checks. New checks
@@ -4476,28 +4417,27 @@ Version 1.7.0beta03 [February 22, 2013]
    for it on then the build will fail if it can't be done.)
  Updated the INSTALL document.

-Version 1.7.0beta04 [February 27, 2013]
+Version 1.6.1beta04 [February 27, 2013]
  Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES.
  Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC.
  Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble
    with CRLF line endings.

-Version 1.7.0beta05 [March 5, 2013]
+Version 1.6.1beta05 [March 1, 2013]
  Avoid a possible memory leak in contrib/gregbook/readpng.c
-  Changed user chunk callback API to respect global and per chunk defaults.
-    Previously a return of 0 from a user chunk callback would result in the
-    chunk being saved (if this was safe, even if the chunk was unsafe-to-copy);
-    this change respects the defaults set by the application, so unknown chunks
-    can be discarded by default and known-safe ones preserved.
+
+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.  The order of settings vs options in
-    pnglibconf.h is reversed to allow settings to depend on options and
-    options can now set (or override) the defaults for settings.
+    compile and link on Android.
+  The order of settings vs options in pnglibconf.h is reversed to allow
+    settings to depend on options and options can now set (or override) the
+    defaults for settings.

-Version 1.7.0beta06 [March 13, 2013]
+Version 1.6.1beta07 [March 7, 2013]
  Corrected simplified API default gamma for color-mapped output, added
    a flag to change default. In 1.6.0 when the simplified API was used
    to produce color-mapped output from an input image with no gamma
@@ -4510,6 +4450,8 @@ Version 1.7.0beta06 [March 13, 2013]
    application/user to specify that 16-bit files contain sRGB data
    rather than the default linear.
  Fixed bugs in the pngpixel and makepng test programs.
+
+Version 1.6.1beta08 [March 7, 2013]
  Fixed CMakelists.txt to allow building a single variant of the library
    (Claudio Bley):
  Introduced a PNG_LIB_TARGETS variable that lists all activated library
@@ -4521,11 +4463,19 @@ Version 1.7.0beta06 [March 13, 2013]
    first argument. When symlinking the filename component of that path is
    determined and used as the link target.
  Use copy_if_different in the CREATE_SYMLINK macro.
+
+Version 1.6.1beta09 [March 13, 2013]
  Eliminated two warnings from the Intel C compiler. The warnings are
    technically valid, although a reasonable treatment of division would
    show it to be incorrect.

-Version 1.7.0beta07 [April 14, 2013]
+Version 1.6.1rc01 [March 21, 2013]
+  No changes.
+
+Version 1.6.1 [March 28, 2013]
+  No changes.
+
+Version 1.6.2beta01 [April 14, 2013]
  Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling.
  Fixed incorrect warning of excess deflate data. End condition - the
    warning would be produced if the end of the deflate stream wasn't read
@@ -4537,45 +4487,46 @@ Version 1.7.0beta07 [April 14, 2013]
  Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c
    (Flavio Medeiros).
  Corrected length written to uncompressed iTXt chunks (Samuli Suominen).
+    Bug was introduced in libpng-1.6.0.

-Version 1.7.0beta08 [April 18, 2013]
+Version 1.6.2rc01 [April 18, 2013]
  Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length
    written by libpng-1.6.0 and 1.6.1.
  Disallow storing sRGB information when the sRGB is not supported.

-Version 1.7.0beta09 [April 24, 2013]
-  Exposed PNG chunk types in png.h
-  Modified png_uint_32 macros/code to make as few assumptions as possible
-    about the hardware.
+Version 1.6.2rc02 [April 18, 2013]
+  Merge pngtest.c with libpng-1.7.0
+
+Version 1.6.2rc03 [April 22, 2013]
+  Trivial spelling cleanup.
+
+Version 1.6.2rc04 and 1.6.2rc05 [omitted]
+
+Version 1.6.2rc06 [April 24, 2013]
+  Reverted to version 1.6.2rc03.  Recent changes to arm/neon support
+    have been ported to libpng-1.7.0beta09 and will reappear in version
+    1.6.3beta01.
+
+Version 1.6.2 [April 25, 2013]
+  No changes.
+
+Version 1.6.3beta01 [April 25, 2013]
  Revised stack marking in arm/filter_neon.S and configure.ac.
  Ensure that NEON filter stuff is completely disabled when switched 'off'.
    Previously the ARM NEON specific files were still built if the option
    was switched 'off' as opposed to being explicitly disabled.

-Version 1.7.0beta10 [April 24, 2013]
-  Attempt to fix the PNG_ARM_NEON configuration mess.
+Version 1.6.3beta02 [April 26, 2013]
+  Test for 'arm*' not just 'arm' in the host_cpu configure variable.
+  Rebuilt the configure scripts.

-Version 1.7.0beta11 [April 26, 2013]
-  Test for 'arm*', not just 'arm' in the host_cpu configure variable.
-
-Version 1.7.0beta12 [April 30, 2013]
-  Added png_app_warning for out-of-range unknown chunk index in
-    png_set_unknown_chunk_location().
-  Expanded manual paragraph about writing private chunks.
+Version 1.6.3beta03 [April 30, 2013]
+  Expanded manual paragraph about writing private chunks, particularly
+    the need to call png_set_keep_unknown_chunks() when writing them.
  Avoid dereferencing NULL pointer possibly returned from
     png_create_write_struct() (Andrew Church).

-Version 1.7.0beta13 [May 12, 2013]
-  Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
-    right zlib header files.
-  Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
-  Updated contrib/pngminus/pnm2png.c (Paul Stewart):
-    Check for EOF
-    Ignore "#" delimited comments in input file to pnm2png.c.
-    Fixed whitespace handling
-    Added a call to png_set_packing()
-    Initialize dimension values so if sscanf fails at least we have known
-      invalid values.
+Version 1.6.3beta05 [May 9, 2013]
  Calculate our own zlib windowBits when decoding rather than trusting the
    CMF bytes in the PNG datastream.
  Added an option to force maximum window size for inflating, which was
@@ -4587,6 +4538,15 @@ Version 1.7.0beta13 [May 12, 2013]
    only works with libpng versions that can be made to reliably fail when
    the deflate data contains an out-of-window reference.  This means only
    1.6 and later.
+  Fixed gnu issues: g++ needs a static_cast, gcc 4.4.7 has a broken warning
+    message which it is easier to work round than ignore.
+  Updated contrib/pngminus/pnm2png.c (Paul Stewart):
+    Check for EOF
+    Ignore "#" delimited comments in input file to pnm2png.c.
+    Fixed whitespace handling
+    Added a call to png_set_packing()
+    Initialize dimension values so if sscanf fails at least we have known
+      invalid values.
  Attempt to detect configuration issues with png-fix-too-far-back, which
    requires both the correct libpng and the correct zlib to function
    correctly.
@@ -4594,11 +4554,21 @@ Version 1.7.0beta13 [May 12, 2013]
  Added information in the documentation about problems with and fixes for
    the bad CRC and bad iTXt chunk situations.

-Version 1.7.0beta14 [June 8, 2013]
+Version 1.6.3beta06 [May 12, 2013]
+  Allow contrib/pngminus/pnm2png.c to compile without WRITE_INVERT and
+    WRITE_PACK supported (writes error message that it can't read P1 or
+    P4 PBM files).
+  Improved png-fix-too-far-back usage message, added --suffix option.
+  Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
+    right zlib header files.
+  Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
+
+Version 1.6.3beta07 [June 8, 2013]
  Removed a redundant test in png_set_IHDR().
  Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt)
  Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
-  Enclose the prototypes for the simplified write API in #ifdef STDIO/#endif
+  Enclose the prototypes for the simplified write API in
+    #ifdef PNG_STDIO_SUPPORTED/#endif
  Make ARM NEON support work at compile time (not just configure time).
    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
    using a compiler that compiles for multiple architectures at one time.
@@ -4618,50 +4588,79 @@ Version 1.7.0beta14 [June 8, 2013]
    the confusion that would result by declaring the init function even when
    it is not used, so that it will always get prefixed.

-Version 1.7.0beta15 [June 18, 2013]
+Version 1.6.3beta08 [June 18, 2013]
  Revised libpng.3 so that "doclifter" can process it.

-Version 1.7.0beta16 [July 5, 2013]
+Version 1.6.3beta09 [June 27, 2013]
  Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
    as parameters for png_set_gamma().  These have been available since
    libpng-1.5.4.
  Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
    to check all compressed chunks known to libpng.
-  Updated documentation to show default behavior of benign errors correctly.
-  Added perfect hash code generation for lists of PNG chunks. This is
-    a work in progress; checked in for use in pngfix.c
-  Ported ARM no-read patch from libpng16.
-  Ported pngfix.c patches from libpng16.

-Version 1.7.0beta17 [August 21, 2013]
+Version 1.6.3beta10 [July 5, 2013]
+  Updated documentation to show default behavior of benign errors correctly.
+  Only compile ARM code when PNG_READ_SUPPORTED is defined.
+  Fixed undefined behavior in contrib/tools/pngfix.c and added new strip
+    option. pngfix relied on undefined behavior and even a simple change from
+    gcc to g++ caused it to fail.  The new strip option 'unsafe' has been
+    implemented and is the default if --max is given.  Option names have
+    been clarified, with --strip=transform now stripping the bKGD chunk,
+    which was stripped previously with --strip=unused.
+  Added all documented chunk types to pngpriv.h
+  Unified pngfix.c source with libpng17.
+
+Version 1.6.3rc01 [July 11, 2013]
+  No changes.
+
+Version 1.6.3 [July 18, 2013]
  Revised manual about changes in iTXt chunk handling made in libpng-1.6.0.
  Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings
    may be erroneously issued by code-checking applications.
+
+Version 1.6.4beta01 [August 21, 2013]
  Added information about png_set_options() to the manual.
  Delay calling png_init_filter_functions() until a row with nonzero filter
    is found.

-Version 1.7.0beta18 [September 16, 2013]
+Version 1.6.4beta02 [August 30, 2013]
  Fixed inconsistent conditional compilation of png_chunk_unknown_handling()
    prototype, definition, and usage.  Made it depend on
    PNG_HANDLE_AS_UNKNOWN_SUPPORTED everywhere.

-Version 1.7.0beta19 [September 30, 2013]
-  Reverted the change to unknown handling #defines; the change breaks 'NOREAD'
-    builds.
-  Fixed default behavior of ARM_NEON_API. If the ARM NEON API option is
-    compiled without the CHECK option it defaulted to on, not off.
-  Catch up with recent libpng16 changes; unknown handling and spelling
-    corrections
+Version 1.6.4rc01 [September 5, 2013]
+  No changes.
+
+Version 1.6.4 [September 12, 2013]
+  No changes.
+
+Version 1.6.5 [September 14, 2013]
+  Removed two stray lines of code from arm/arm_init.c.
+
+Version 1.6.6 [September 16, 2013]
+  Removed two stray lines of code from arm/arm_init.c, again.
+
+Version 1.6.7beta01 [September 30, 2013]
+  Revised unknown chunk code to correct several bugs in the NO_SAVE_/NO_WRITE
+    combination
+  Allow HANDLE_AS_UNKNOWN to work when other options are configured off. Also
+    fixed the pngminim makefiles to work when $(MAKEFLAGS) contains stuff
+    which terminates the make options (as by default in recent versions of
+    Gentoo).
  Avoid up-cast warnings in pngvalid.c. On ARM the alignment requirements of
    png_modifier are greater than that of png_store and as a consequence
    compilation of pngvalid.c results in a warning about increased alignment
-    requirements because of the bare cast to (png_modifier*).  The code is
-    safe, because the pointer is known to point to a stack allocated
-    png_modifier, but this change avoids the warning.
-  Fixed some grammatical changes and updated the png chunks list.
+    requirements because of the bare cast to (png_modifier*). The code is safe,
+    because the pointer is known to point to a stack allocated png_modifier,
+    but this change avoids the warning.
+  Fixed default behavior of ARM_NEON_API. If the ARM NEON API option was
+    compiled without the CHECK option it defaulted to on, not off.
+  Check user callback behavior in pngunknown.c. Previous versions compiled
+    if SAVE_UNKNOWN was not available but did nothing since the callback
+    was never implemented.
+  Merged pngunknown.c with 1.7 version and back ported 1.7 improvements/fixes

-Version 1.7.0beta20 [October 13, 2013]
+Version 1.6.7beta02 [October 12, 2013]
  Made changes for compatibility with automake 1.14:
    1) Added the 'compile' program to the list of programs that must be cleaned
       in autogen.sh
@@ -4687,13 +4686,15 @@ Version 1.7.0beta20 [October 13, 2013]
  Make autogen.sh work with automake 1.13 as well as 1.14. Do this by always
    removing the 1.14 'compile' script but never checking for it.

-Version 1.7.0beta21 [November 2, 2013]
+Version 1.6.7beta03 [October 19, 2013]
  Added ARMv8 support (James Yu <james.yu at linaro.org>).  Added file
    arm/filter_neon_intrinsics.c; enable with -mfpu=neon.
  Revised pngvalid to generate size images with as many filters as it can
    manage, limited by the number of rows.
  Cleaned up ARM NEON compilation handling. The tests are now in pngpriv.h
    and detect the broken GCC compilers.
+
+Version 1.6.7beta04 [October 26, 2013]
  Allow clang derived from older GCC versions to use ARM intrinsics. This
    causes all clang builds that use -mfpu=neon to use the intrinsics code,
    not the assembler code.  This has only been tested on iOS 7. It may be
@@ -4703,14 +4704,17 @@ Version 1.7.0beta21 [November 2, 2013]
    PNG_ARM_NEON_IMPLEMENTATION to the correct value (2 or 1).  This macro
    is undefined by default and the build type is selected in pngpriv.h.

-Version 1.7.0beta22 [November 7, 2013]
+Version 1.6.7rc01 [November 2, 2013]
+  No changes.
+
+Version 1.6.7rc02 [November 7, 2013]
  Fixed #include in filter_neon_intrinsics.c and ctype macros. The ctype char
    checking macros take an unsigned char argument, not a signed char.

-Version 1.7.0beta23 [November 24, 2013]
-  Changed #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED in pngpread.c to
-    #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED to be consistent with
-    what is in pngpriv.h.
+Version 1.6.7 [November 14, 2013]
+  No changes.
+
+Version 1.6.8beta01 [November 24, 2013]
  Moved prototype for png_handle_unknown() in pngpriv.h outside of
    the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
  Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
@@ -4726,13 +4730,28 @@ Version 1.7.0beta23 [November 24, 2013]
    This reverts to the previous 'static' implementation and works round
    the 'unused static function' warning by using PNG_UNUSED().

-Version 1.7.0beta24 [December 15, 2013]
+Version 1.6.8beta02 [November 30, 2013]
  Removed or marked PNG_UNUSED some harmless "dead assignments" reported
    by clang scan-build.
  Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
    to '"%s" m' to improve portability among compilers.
  Changed png_free_default() to free() in pngtest.c
+
+Version 1.6.8rc01 [December 12, 2013]
  Tidied up pngfix inits and fixed pngtest no-write builds.
+
+Version 1.6.8rc02 [December 14, 2013]
+  Handle zero-length PLTE chunk or NULL palette with png_error()
+    instead of png_chunk_report(), which by default issues a warning
+    rather than an error, leading to later reading from a NULL pointer
+    (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
+    and VU#650142.  Libpng-1.6.1 through 1.6.7 are vulnerable.
+    Libpng-1.6.0 and earlier do not have this bug.
+
+Version 1.6.8 [December 19, 2013]
+  No changes.
+
+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 made static. Move the intrapixel functions and the
@@ -4745,60 +4764,50 @@ Version 1.7.0beta24 [December 15, 2013]
    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.
-  Handle zero-length PLTE chunk or NULL palette with png_error()
-    instead of png_chunk_report(), which by default issues a warning
-    rather than an error, leading to later reading from a NULL pointer
-    (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
-    and VU#650142.  Libpng-1.6.1 through 1.6.7 and libpng-1.7.0beta03
-    through 1.7.0beta23 are vulnerable.  Libpng-1.6.0 and earlier do not
-    have the bug.
-
-Version 1.7.0beta25 [December 26, 2013]
-  Merged files with version 1.6.8 that have not changed since then.
  Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69
+    in the tar distributions.

-Version 1.7.0beta26 [January 1, 2014]
-  Added libpng 1.5 checks to pngvalid.c
-  Merged with 1.5 and 1.6 changes to create a single pngvalid.c
-  Added dSIG to chunk list in png.h
+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, and pngwio.c with libpng-1.6.9
-  Fixed test programs for interlace options. Made pngvalid.c and
-    pngtest.c work correctly when READ_INTERLACING and/or WRITE_INTERLACING
-    are switched off.
-  Changed 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
+  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.

-Version 1.7.0beta27 [January 10, 2014]
+Version 1.6.9beta03 [January 10, 2014]
  Removed potentially misleading warning from png_check_IHDR().

-Version 1.7.0beta28 [January 20, 2014]
+Version 1.6.9beta04 [January 20, 2014]
  Updated scripts/makefile.* to use CPPFLAGS (Cosmin).
  Added clang attribute support (Cosmin).

-Version 1.7.0beta29 [January 30, 2014]
-  Quiet an uninitialized memory warning from VS2013 in png_get_png().
+Version 1.6.9rc01 [January 28, 2014]
+  No changes.

-Version 1.7.0beta30 [February 2, 2014]
+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. This
-    is a work-in-progress; no tests are run automatically at present and
-    the program by virtue of exhaustively testing all the transforms is
-    very slow.
-
-Version 1.7.0beta31 [February 6, 2014]
-  Make png_read_png() and png_write_png() prototypes in png.h depend
-    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
+  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().
-  Completed full working pngimage test program and added two test scripts.
  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
@@ -4809,10 +4818,8 @@ Version 1.7.0beta31 [February 6, 2014]
    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).
-  Restored a line, "c = b;", that was inadvertently deleted from the
-    PAETH filtering code from libpng-1.7.0beta24/pngrutil.c. Deleted
-    the other instance of "c = b;" which is the one that triggered a
-    scan-build warning.
+  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
@@ -4822,7 +4829,7 @@ Version 1.7.0beta31 [February 6, 2014]
    and it adds corresponding code to pngimage.c to handle such options
    by not attempting to test them.

-Version 1.7.0beta32 [February 26, 2014]
+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.
@@ -4839,6 +4846,8 @@ Version 1.7.0beta32 [February 26, 2014]
    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
@@ -4847,20 +4856,44 @@ Version 1.7.0beta32 [February 26, 2014]
    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.
-  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
-  Moved some documentation from png.h to libpng.3 and libpng-manual.txt

-Version 1.7.0beta33 [February 27, 2014]
+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 1.7.0beta34 [March 17, 2014]
-  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.
+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).
+  $(CP) is now used alongside $(RM_F).  Also, use 'copy' instead
+    of 'cp' where applicable, and applied other minor makefile changes.
+  Don't warn about invalid dimensions exceeding user limits.
+  Allow an easy replacement of the default pre-built configuration
+    header with a custom header, via the make PNGLIBCONF_H_PREBUILT
+    macro.
+  Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes
+    with "blocky" expansion of sub-8-bit interlaced PNG files.
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,8 +15,8 @@ project(libpng C)
 enable_testing()

 set(PNGLIB_MAJOR 1)
-set(PNGLIB_MINOR 7)
-set(PNGLIB_RELEASE 0)
+set(PNGLIB_MINOR 6)
+set(PNGLIB_RELEASE 11)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

@@ -252,9 +252,9 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#   VERSION 17.${PNGLIB_RELEASE}.1.7.0beta34
-    VERSION 17.${PNGLIB_RELEASE}.0
-    SOVERSION 17
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.11beta02
+    VERSION 16.${PNGLIB_RELEASE}.0
+    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
 endif()
 if(PNG_STATIC)
@@ -286,7 +286,7 @@ if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})

  if(PNG_SHARED)
-    # Create a symlink for libpng.dll.a => libpng17.dll.a on Cygwin
+    # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin
    if(CYGWIN OR MINGW)
       get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME} LOCATION_${CMAKE_BUILD_TYPE})
       CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_IMPORT_LIBRARY_SUFFIX})
--- a/5
+++ b/5
@@ -52,6 +52,7 @@ 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
@@ -155,7 +156,9 @@ 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.
--- 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 1.7.0beta34, March 17, 2014, are
+libpng versions 1.2.6, August 15, 2004, through 1.6.11beta02, April 6, 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
-March 17, 2014
+April 6, 2014
--- a/Makefile.am
+++ b/Makefile.am
@@ -145,8 +145,8 @@ config.sub configure depcomp install-sh ltmain.sh missing
 PNG_COPTS = @PNG_COPTS@
 AM_CFLAGS = ${PNG_COPTS}

-# DFNCPP is normally just "CPP -E" - the C preprocessor - but on Solaris and
-# maybe other operating systems (NeXT?) the C preprocessor selected by configure
+# DFNCPP is normally just CPP - the C preprocessor - but on Solaris and maybe
+# other operating systems (NeXT?) the C preprocessor selected by configure
 # checks input tokens for validity - effectively it performs part of the ANSI-C
 # parsing - and therefore fails with the .df files.  configure.ac has special
 # checks for this and sets DFNCPP appropriately.
@@ -165,8 +165,6 @@ scripts/prefix.out: png.h pngconf.h pnglibconf.out
 scripts/symbols.out: png.h pngconf.h $(srcdir)/scripts/pnglibconf.h.prebuilt
 scripts/intprefix.out: pnglibconf.h

-pnglibconf.out: config.h
-
 libpng.sym: scripts/sym.out
 	rm -f $@
 	cp $? $@
@@ -178,7 +176,7 @@ if DO_PNG_PREFIX
 # Rename functions in scripts/prefix.out with a PNG_PREFIX prefix.
 # Rename macros in scripts/macro.lst from PNG_PREFIXpng_ to PNG_ (the actual
 # implementation of the macro).
-pnglibconf.h: pnglibconf.out scripts/prefix.out scripts/macro.lst config.h
+pnglibconf.h: pnglibconf.out scripts/prefix.out scripts/macro.lst
 	rm -f $@
 	$(AWK) 's==0 && NR>1{print prev}\
 	   s==0{prev=$$0}\
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-README for libpng version 1.7.0beta34 - March 17, 2014 (shared library 17.0)
+README for libpng version 1.6.11beta02 - April 6, 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.
--- a/configure.ac
+++ b/configure.ac
@@ -18,7 +18,7 @@ AC_PREREQ([2.68])

 dnl Version number stuff here:

-AC_INIT([libpng],[1.7.0beta34],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.11beta02],[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=1.7.0beta34
+PNGLIB_VERSION=1.6.11beta02
 PNGLIB_MAJOR=1
-PNGLIB_MINOR=7
-PNGLIB_RELEASE=0
+PNGLIB_MINOR=6
+PNGLIB_RELEASE=11

 dnl End of version number stuff

@@ -79,7 +79,7 @@ fi

 # This is a remnant of the old cc -E validation, where it may have been
 # necessary to use a different preprocessor for .dfn files
-DFNCPP="$CPP -E"
+DFNCPP="$CPP"
 AC_SUBST(DFNCPP)

 # -Werror cannot be passed to GCC in CFLAGS because configure will fail (it
@@ -109,146 +109,30 @@ AC_ARG_ENABLE(werror,

 # Checks for header files.
 AC_HEADER_STDC
-# Headers used in pngpriv.h:
-AC_CHECK_HEADERS([assert.h stdlib.h string.h float.h fp.h math.h m68881.h])
-# Additional headers used in pngconf.h:
-AC_CHECK_HEADERS([limits.h stddef.h stdio.h setjmp.h time.h])
-# Used by pngread.c (for the simplified API):
-AC_CHECK_HEADERS([errno.h])
-# The following are not required for the standard 'make' build of libpng:
-# Additional requirements of contrib/libtests/makepng.c:
-AC_CHECK_HEADERS([ctype.h])
-# Additional requirements of contrib/libtests/pngvalid.c:
-AC_CHECK_HEADERS([fenv.h])

 # Checks for typedefs, structures, and compiler characteristics.
-# Most of these have been removed from 1.7.0 because they checked for non-ANSI-C
-# behaviors and the result were, anyway, not used by earlier versions of libpng.
+AC_C_CONST
+AC_TYPE_SIZE_T
+AC_STRUCT_TM
 AC_C_RESTRICT

-# Checks for library functions; these need to be in order, least demanding to
-# most because the -l directives are added to the head of the list at each
-# check.
-# ANSI-C functions: all are required but they don't have to be implemented in
-# libc, it is perfectly ok to configure with an extra, wrapper, library preset
-# in LIBS.  NOTE: this list may not be complete
-AC_CHECK_FUNCS([memset memcpy strncpy],,
-               AC_MSG_FAILURE([missing ANSI-C functions]))
-
-# floor and ceil are required for FLOATING_POINT, but they can be turned off on
-# the configure command line (and they are independent.)  Default is to 'on'
-AC_ARG_ENABLE([floating-point],
-   AS_HELP_STRING([[[--enabled-floating-point]]],
-      [Enable floating point APIs (default: yes)]),,
-   [enable_floating_point=yes])
-
-AC_ARG_ENABLE([fixed-point],
-   AS_HELP_STRING([[[--enable-fixed-point]]],
-      [Enable fixed point APIs (default: yes)]),,
-   [enable_fixed_point=yes])
-
-AC_ARG_ENABLE([floating-arithmetic],
-   AS_HELP_STRING([[[--enable-floating-arithmetic]]],
-      [Use floating point arithmetic internally (default: yes)]),,
-   [enable_floating_arithmetic=yes])
-
-# Check for a requirement for math library support
-if test "$enable_floating_arithmetic" = yes
-then
-   AC_SEARCH_LIBS([floor],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-   AC_SEARCH_LIBS([frexp],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-   AC_SEARCH_LIBS([modf],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-   AC_SEARCH_LIBS([atof],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-   AC_SEARCH_LIBS([pow],[m],,
-                  [AC_MSG_WARN([not found])
-                   enable_floating_arithmetic=no])
-fi
-
-# Set the relevant defines if required (only if required), this will override
-# anything on the command line.
-if test "$enable_floating_point" != yes
-then
-   AC_MSG_NOTICE([Floating point APIs disabled])
-   AC_DEFINE([PNG_NO_FLOATING_POINT],[1],
-             [No support for floating point APIs])
-fi
-if test "$enable_fixed_point" != yes
-then
-   AC_MSG_NOTICE([Fixed point APIs disabled])
-   AC_DEFINE([PNG_NO_FIXED_POINT],[1],
-             [No support for fixed point APIs])
-fi
-if test "$enable_floating_arithmetic" != yes
-then
-   AC_MSG_NOTICE([Fixed point arithmetic will be used])
-   AC_DEFINE([PNG_NO_FLOATING_ARITHMETIC],[1],
-             [No support for floating point arithmetic])
-fi
+# Checks for library functions.
+AC_FUNC_STRTOD
+AC_CHECK_FUNCS([memset], , AC_MSG_ERROR(memset not found in libc))
+AC_CHECK_FUNCS([pow], , AC_CHECK_LIB(m, pow, , AC_MSG_ERROR(cannot find pow)) )
+AC_ARG_WITH(zlib-prefix,
+   AS_HELP_STRING([[[--with-zlib-prefix]]],
+      [prefix that may have been used in installed zlib]),
+      [ZPREFIX=${withval}],
+      [ZPREFIX='z_'])
+AC_CHECK_LIB(z, zlibVersion, ,
+    AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, , AC_MSG_ERROR(zlib not installed)))

 # The following is for pngvalid, to ensure it catches FP errors even on
 # platforms that don't enable FP exceptions, the function appears in the math
 # library (typically), it's not an error if it is not found.
-AC_SEARCH_LIBS([feenableexcept],[m],AC_DEFINE([HAVE_FEENABLEEXCEPT],[1],
-      [Define to 1 if the feenableexcept function is available]))
-# Required by pngvalid:
-AC_SEARCH_LIBS([ceil],[m])
-
-# zlib checks and arguments;
-#  package zlib: argument is the name of the library
-#  zlib-header: the name of the header file
-#  zlib-prefix: the prefix for library functions, if any
-AC_ARG_WITH([zlib],
-   AS_HELP_STRING([[[--with-zlib=<name>]]],
-                  [base name of the zlib implementation (e.g. 'z')]),,
-   [with_zlib='z'])
-
-z_prefix=
-AC_ARG_WITH([zlib-prefix],
-   AS_HELP_STRING([[[--with-zlib-prefix=<prefix>]]],
-                  [prefix for zlib API functions]),
-   [if test "$withval" = "" -o "$withval" = yes; then
-      with_zlib_prefix='z_'
-      AC_DEFINE([PNG_ZLIB_PREFIX],[z_],[Standard zlib prefix])
-   elif test "${withval}" != "no"; then
-      AC_DEFINE_UNQUOTED([PNG_ZLIB_PREFIX],[${withval}],
-         [User defined zlib prefix])
-   else
-      with_zlib_prefix=
-   fi
-   if test "$with_zlib_prefix" != ""; then
-      AC_DEFINE([Z_PREFIX],[1],[Tell zlib.h to prefix function names])
-      z_prefix="#define Z_PREFIX 1"
-   fi])
-
-AC_ARG_WITH([zlib-header],
-   AS_HELP_STRING([[[--with-zlib-header='<file>' or '"file"']]],
-      [C include argument to locate zlib header file, e.g. <zlib.h>, take
-       care to put single quotes round this on the command line]),
-   [AC_DEFINE_UNQUOTED([PNG_ZLIB_HEADER],[${withval}],[Zlib header file])],
-   with_zlib_header='<zlib.h>')
-
-# AC_CHECK_LIB isn't quite enough for this because we need the special header
-# file too.
-LIBS="-l${with_zlib} $LIBS"
-AC_MSG_CHECKING(
-   [[Library '${with_zlib}' and #include ${with_zlib_header} for symbol '${with_zlib_prefix}zlibVersion']])
-AC_LINK_IFELSE(
-   [AC_LANG_PROGRAM(
-      [[
-${z_prefix}
-#include ${with_zlib_header}
-      ]],
-      [[(void)${with_zlib_prefix}zlibVersion();]])],
-   AC_MSG_RESULT([ok]),
-   AC_MSG_FAILURE([not found]))
+AC_CHECK_LIB([m], [feenableexcept])
+AC_CHECK_FUNCS([feenableexcept])

 AC_MSG_CHECKING([if using Solaris linker])
 SLD=`$LD --version 2>&1 | grep Solaris`
@@ -294,7 +178,7 @@ AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
 if test "$have_ld_version_script" = "yes"; then
    AC_MSG_CHECKING([for symbol prefix])
    SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
-                  | ${DFNCPP-${CC-gcc -E}} - 2>&1 \
+                  | ${CPP-${CC-gcc} -E} - 2>&1 \
                  | ${EGREP-grep} "^PREFIX=" \
                  | ${SED-sed} -e "s:^PREFIX=::" -e "s:__USER_LABEL_PREFIX__::"`
    AC_SUBST(SYMBOL_PREFIX)
@@ -433,7 +317,8 @@ AM_CONDITIONAL([PNG_ARM_NEON],
 AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])

 # Config files, substituting as above
-AC_CONFIG_FILES([Makefile libpng.pc])
-AC_CONFIG_FILES([libpng-config], [chmod +x libpng-config])
+AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])
+AC_CONFIG_FILES([libpng-config:libpng-config.in],
+   [chmod +x libpng-config])

 AC_OUTPUT
--- a/contrib/conftest/README
+++ b/contrib/conftest/README
@@ -16,6 +16,9 @@ directory it is very unlikely that it will be tested before a minor release!
 You can use these .dfa files as the basis of new configurations.  Files in this
 directory should not have any use restrictions or restrictive licenses.

+This directory is not included in the .zip and .7z distributions, which do
+not contain 'configure' scripts.
+
 DOCUMENTATION
 =============

--- a/contrib/gregbook/Makefile.sgi
+++ b/contrib/gregbook/Makefile.sgi
@@ -23,9 +23,9 @@

 # macros --------------------------------------------------------------------

-PNGINC = -I/usr/local/include/libpng17
-PNGLIB = -L/usr/local/lib -lpng17	  # dynamically linked against libpng
-#PNGLIB = /usr/local/lib/libpng17.a # statically linked against libpng
+PNGINC = -I/usr/local/include/libpng16
+PNGLIB = -L/usr/local/lib -lpng16	  # dynamically linked against libpng
+#PNGLIB = /usr/local/lib/libpng16.a # statically linked against libpng
 # or:
 #PNGINC = -I../..
 #PNGLIB = -L../.. -lpng
--- a/contrib/gregbook/Makefile.unx
+++ b/contrib/gregbook/Makefile.unx
@@ -26,14 +26,14 @@
 # macros --------------------------------------------------------------------

 #PNGDIR = /usr/local/lib
-#PNGINC = -I/usr/local/include/libpng17
-#PNGLIBd = -L$(PNGDIR) -lpng17 # dynamically linked, installed libpng
-#PNGLIBs = $(PNGDIR)/libpng17.a # statically linked, installed libpng
+#PNGINC = -I/usr/local/include/libpng16
+#PNGLIBd = -L$(PNGDIR) -lpng16 # dynamically linked, installed libpng
+#PNGLIBs = $(PNGDIR)/libpng16.a # statically linked, installed libpng
 # or:
 PNGDIR = ../..#	this one is for libpng-x.y.z/contrib/gregbook builds
 #PNGDIR = ../libpng
 PNGINC = -I$(PNGDIR)
-PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng17	# dynamically linked
+PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng16	# dynamically linked
 PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng

 ZDIR = /usr/local/lib
--- 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 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.10 [March 6, 2014]
 * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by John Cunningham Bowler
 *
@@ -386,9 +386,9 @@ 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;

@@ -3155,10 +3155,10 @@ 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
   }
 }

@@ -6776,14 +6776,14 @@ 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
@@ -6801,13 +6801,12 @@ 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
      }
   }

@@ -9273,6 +9272,28 @@ static void gamma_composition_test(png_modifier *pm,
      r = random_32();
      background.blue = (png_uint_16)r;
      background.gray = (png_uint_16)(r >> 16);
+
+      /* In earlier libpng versions, those where DIGITIZE is set, any background
+       * gamma correction in the expand16 case was done using 8-bit gamma
+       * correction tables, resulting in larger errors.  To cope with those
+       * cases use a 16-bit background value which will handle this gamma
+       * correction.
+       */
+#     if DIGITIZE
+         if (expand_16 && (do_background == PNG_BACKGROUND_GAMMA_UNIQUE ||
+                           do_background == PNG_BACKGROUND_GAMMA_FILE) &&
+            fabs(bg*screen_gamma-1) > PNG_GAMMA_THRESHOLD)
+         {
+            /* The background values will be looked up in an 8-bit table to do
+             * the gamma correction, so only select values which are an exact
+             * match for the 8-bit table entries:
+             */
+            background.red = (png_uint_16)((background.red >> 8) * 257);
+            background.green = (png_uint_16)((background.green >> 8) * 257);
+            background.blue = (png_uint_16)((background.blue >> 8) * 257);
+            background.gray = (png_uint_16)((background.gray >> 8) * 257);
+         }
+#     endif
   }

   else /* 8 bit colors */
--- 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/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/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/pngminus/makefile.std
+++ b/contrib/pngminus/makefile.std
@@ -8,9 +8,9 @@ LD=$(CC)
 RM=rm -f

 #PNGPATH = /usr/local
-#PNGINC = -I$(PNGPATH)/include/libpng17
-#PNGLIB = -L$(PNGPATH)/lib -lpng17
-#PNGLIBS = $(PNGPATH)/lib/libpng17.a
+#PNGINC = -I$(PNGPATH)/include/libpng16
+#PNGLIB = -L$(PNGPATH)/lib -lpng16
+#PNGLIBS = $(PNGPATH)/lib/libpng16.a
 PNGINC = -I../..
 PNGLIB = -L../.. -lpng
 PNGLIBS = ../../libpng.a
@@ -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/tools/chunkhash.c
+++ b/contrib/tools/chunkhash.c
@@ -1,437 +0,0 @@
-/* chunkhash.c -- build a perfect hash code for the chunk names on stdin.
- *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- *
- * COPYRIGHT: Written by John Cunningham Bowler, 2014.
- * To the extent possible under law, the author has waived all copyright and
- * related or neighboring rights to this work.  This work is published from:
- * United States.
- *
- * Feed this program all the known chunks that libpng must recognize.  It will
- * generate an appropriate hash key for the macro in pngpriv.h  To generate the
- * list of chunks currently defined in png.h do this:
- *
- *    sed -n -e 's/^#define png_\(....\) PNG_U32.*$/\1/p' png.h
- *
- * An alternative to using this program is to pipe the output of the above
- * through gperf, however the code generated by perf is somewhat more verbose
- * and it doesn't generate as good a result (however it's a heck of a lot faster
- * than this program!)
- */
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <png.h> /* for the libpng types for this platform */
-
-/* The machine generated file is checked in, so this works and it obtains the
- * definition of the PNG_CHUNK_HASH macro.  To change this definition only ever
- * alter the strings below!
- */
-#include "chunkhash.h"
-
-/* The best_ variables are local variables defined in the functions below.  When
- * used in libpng code, however, they are just constants.
- */
-#define PNG_CHUNK_HASH_MASK best_mask
-#define PNG_CHUNK_HASH_C0 best_c[0]
-#define PNG_CHUNK_HASH_C1 best_c[1]
-#define PNG_CHUNK_HASH_C2 best_c[2]
-#define PNG_CHUNK_HASH_C3 best_c[3]
-
-/* These strings contain the C text to copy into the new version of
- * contrib/tools/chunkhash.c
- */
-static const char *strings[] = {
-"/* chunkhash.h -- a perfect hash code for the chunk names in png.h",
-" *",
-" * Last changed in libpng 1.7.0 [(PENDING RELEASE)]",
-" *",
-" * THIS IS A MACHINE GENERATED FILE.  See contrib/tools/chunkhash.c for",
-" * copyright and other information.",
-" *",
-" * USAGE:  To include the PNG_CHUNK_HASH macro and associated definitions:",
-" *",
-" * #define PNG_CHUNKHASH_DEFS",
-" * #include \"contrib/tools/chunkhash.h\"",
-" *",
-" * To define the png_chunk_hash array used by the macro:",
-" *",
-" * #define PNG_CHUNKHASH_CODE",
-" * #include \"contrib/tools/chunkhash.h\"",
-" *",
-" * One or both of the defines must be given except when building chunkhash",
-" * itself.",
-" */",
-"#ifdef PNG_CHUNKHASH_DEFS",
-"#ifndef PNG_CHUNKHASH_H",
-"#define PNG_CHUNKHASH_H",
-"/* A perfect hash code - returns a value 0..(PNG_KNOWN_CHUNK_COUNT-1) and is",
-" * generated by the ridiculously simple program in contrib/tools/chunkhash.c",
-" *",
-" * The hash code used here multiplies each byte by a different constant to",
-" * return a single number:",
-" *",
-" *    b0 * c[0] + b1 * [c1] + b2 * c[2] + b3 * c[3]",
-" *",
-" * The values of the constants are found by search using the a table of",
-" * primes, including 0, and may be (in fact are at present) 0 for some of the",
-" * bytes, the compiler is expected to optimize multiply by zero, or one!",
-" *",
-" * The lookup table reduces the sparse result of the hash calculation to the",
-" * correct index values.  The chunks are indexed in the string order of the",
-" * png_uint_32 chunk names.",
-" */",
-0, /* HEADER definitions go here */
-"",
-"extern const png_byte png_chunk_hash[PNG_CHUNK_HASH_MASK+1];",
-"#endif /* !PNG_CHUNKHASH_H */",
-"#endif /* PNG_CHUNKHASH_DEFS */",
-"",
-"#ifndef PNG_CHUNK_HASH",
-"#define PNG_CHUNK_HASH(chunk) (png_chunk_hash[PNG_CHUNK_HASH_MASK & (\\",
-"      ((chunk) >> 24) * PNG_CHUNK_HASH_C0 +\\",
-"      ((chunk) >> 16) * PNG_CHUNK_HASH_C1 +\\",
-"      ((chunk) >>  8) * PNG_CHUNK_HASH_C2 +\\",
-"      ((chunk)      ) * PNG_CHUNK_HASH_C3)])",
-"#endif",
-"",
-"#ifdef PNG_CHUNKHASH_CODE",
-"#ifndef PNG_CHUNKHASH_C",
-"#define PNG_CHUNKHASH_C",
-"const png_byte png_chunk_hash[PNG_CHUNK_HASH_MASK+1] = {",
-0, /* png.c definitions go here */
-"};",
-"#endif /* !PNG_CHUNKHASH_C */",
-"#endif /* PNG_CHUNKHASH_CODE */",
-0 /* end of file */
-};
-
-#define CHUNK_COUNT_MAX 32
-   /* If necessary this is easy to increase; just don't use a png_uint_32
-    * bitmask below, however it doesn't seem likely that the limit will be hit
-    * any time soon.
-    */
-
-static const png_byte
-chunk_hash[256] =
-{
-   0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
-   22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
-   41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
-   60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78,
-   79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
-   98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113,
-   114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128,
-   129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143,
-   144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158,
-   159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173,
-   174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188,
-   189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203,
-   204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218,
-   219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233,
-   234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248,
-   249, 250, 251, 252, 253, 254, 255
-};
-
-static void
-error(const char *string)
-{
-   fprintf(stderr, "chunkhash: %s\n", string);
-   exit(1);
-}
-
-/* Return a hash code for the given chunk; this is the same as the pngpriv.h
- * macro, but parameterized.  The names of the parameters have to be chosen to
- * match the above #defines.
- */
-static png_uint_32
-test_hash(png_uint_32 chunk, const unsigned int *best_c, png_uint_32 best_mask)
-{
-#  define png_chunk_hash chunk_hash /* prevents lookup */
-      return PNG_CHUNK_HASH(chunk);
-#  undef png_chunk_hash
-}
-
-static void
-print_chunks(const png_uint_32 *chunks, unsigned int nchunks, png_uint_32 first,
-   png_uint_32 last, const unsigned int *best_c, png_uint_32 best_mask,
-   const png_byte *lut)
-{
-   /* 'last' is the last code to print plus 1, this is used to detect duplicates
-    * (which should not happen - if there are any it's an internal error!)
-    */
-   if (nchunks > 0)
-   {
-      /* Recursive algorithm; find the hash code of the next chunk, then print
-       * all remaining chunks with codes in the range first..code (including
-       * duplicates) and after print all remaining chunks with codes in the
-       * range (code+1)..last
-       */
-      const png_uint_32 chunk = *chunks++;
-#     define png_chunk_hash lut
-         const png_uint_32 code = PNG_CHUNK_HASH(chunk);
-#     undef png_chunk_hash
-
-      --nchunks;
-
-      /* The code might be out of the print range */
-      if (code >= first && code <= last)
-      {
-         if (code >= first) /* not time yet */
-            print_chunks(chunks, nchunks, first, code, best_c, best_mask, lut);
-
-         printf("#define PNG_CHUNK_%c%c%c%c_TAG %lu%s\n", (char)(chunk>>24),
-            (char)(chunk>>16), (char)(chunk>>8), (char)chunk,
-            (unsigned long)code, code == last ? " /* DUPLICATE */" : "");
-
-         if (code < last) /* still some to go */
-            print_chunks(chunks, nchunks, code+1, last, best_c, best_mask, lut);
-      }
-
-      else
-         print_chunks(chunks, nchunks, first, last, best_c, best_mask, lut);
-   }
-}
-
-static unsigned int primes[] =
-{
-   0, 1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67,
-   71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149,
-   151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229,
-   233, 239, 241, 251
-};
-
-#define NPRIMES ((sizeof primes)/(sizeof primes[0]))
-
-int
-main(void)
-{
-   /* Stdin should just contain chunk names, one per line */
-   png_uint_32 best_mask;
-   unsigned int best_c[4];
-   png_uint_32 chunks[CHUNK_COUNT_MAX];
-   png_byte known_chunk_count;
-
-   /* Not required; stop GCC whining: */
-   memset(best_c, 0xab, sizeof best_c);
-   best_mask = 0x12345678;
-
-   {
-      png_uint_32 this_chunk = 0;
-      png_byte n_chunks = 0;
-
-      for (;;)
-      {
-         int ch = getchar();
-
-         if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z'))
-         {
-            if (this_chunk > 0xffffffU)
-               error("chunk name too long");
-
-            this_chunk = (this_chunk << 8) + (unsigned)ch;
-         }
-
-         else
-         {
-            if (this_chunk > 0)
-            {
-               if (this_chunk <= 0xffffffU)
-                  error("chunk name too short");
-
-               if (n_chunks >= CHUNK_COUNT_MAX)
-                  error("too many chunks (check CHUNK_COUNT_MAX)");
-
-               chunks[n_chunks++] = this_chunk;
-               this_chunk = 0;
-            }
-         }
-
-         if (ch < 0)
-            break;
-      }
-
-      /* 22 is the number of chunks currently defined (excluding fRAc), at any
-       * time it should also be in PNG_KNOWN_CHUNK_COUNT, but this run of
-       * chunkhash may be trying to add a chunk so allow bigger numbers.
-       */
-#     ifdef PNG_KNOWN_CHUNK_COUNT
-#        define CHUNK_COUNT_MIN PNG_KNOWN_CHUNK_COUNT
-#     else
-#        define CHUNK_COUNT_MIN 26
-#     endif
-      if (n_chunks < CHUNK_COUNT_MIN)
-         error("too few chunks (expecting at least 26)");
-
-      known_chunk_count = n_chunks;
-   }
-
-   /* Exhaustive search of the hash parameters - in fact this isn't very slow at
-    * all.
-    */
-   {
-      unsigned int i1, c_zero = 0, c_one = 0;
-
-      for (i1=0; i1<NPRIMES; ++i1)
-      {
-         unsigned int i2;
-         unsigned int c[4];
-
-         fprintf(stderr, "TEST: %u\n", primes[i1]);
-         c[0] = primes[i1];
-
-         for (i2=0; i2<NPRIMES; ++i2)
-         {
-            unsigned int i3;
-
-            c[1] = primes[i2];
-
-            for (i3=0; i3<NPRIMES; ++i3)
-            {
-               unsigned int i4;
-
-               c[2] = primes[i3];
-
-               for (i4=0; i4<NPRIMES; ++i4)
-               {
-                  unsigned int i;
-                  png_uint_32 hash_mask = 0xffU;
-                  png_uint_32 hashes[CHUNK_COUNT_MAX];
-
-                  c[3] = primes[i4];
-
-                  while (hash_mask > 0xfU)
-                  {
-                     for (i=0; i<known_chunk_count; ++i)
-                     {
-                        unsigned int j;
-                        png_uint_32 hash = test_hash(chunks[i], c, hash_mask);
-
-                        for (j=0; j<i; ++j) if (hashes[j] == hash) goto next_i4;
-
-                        hashes[i] = hash;
-                     }
-
-                     hash_mask >>= 1;
-                  }
-
-               next_i4:
-                  if (hash_mask < 0xffU)
-                  {
-                     /* This worked */
-                     unsigned int best, c0 = 0, c1 = 0;
-
-                     hash_mask <<= 1;
-                     hash_mask += 1;
-
-                     for (i=0; i<4; ++i)
-                     {
-                        if (c[i] == 0)
-                           ++c0;
-
-                        else if (c[i] == 1)
-                           ++c1;
-                     }
-
-                     if (hash_mask == best_mask)
-                        best = (c0 > c_zero) || (c0 == c_zero && c1 > c_one);
-
-                     else
-                        best = (hash_mask < best_mask);
-
-                     if (best)
-                     {
-                        fprintf(stderr, "{%u,%u,%u,%u} & 0x%lx\n",
-                           c[0], c[1], c[2], c[3],
-                           (unsigned long)hash_mask);
-
-                        c_zero = c0;
-                        c_one = c1;
-                        best_mask = hash_mask;
-                        memcpy(best_c, c, sizeof best_c);
-                     }
-                  }
-               } /* i4 */
-            } /* i3 */
-         } /* i2 */
-      } /* i1 */
-   }
-
-   /* Calculate the LUT (png_chunk_hash) */
-   {
-      png_byte b;
-      png_byte lut[256];
-
-      /* A failure returns PNG_KNOWN_CHUNK_COUNT: */
-      memset(lut, known_chunk_count, sizeof lut);
-
-      for (b=0; b<known_chunk_count; ++b)
-         lut[test_hash(chunks[b], best_c, best_mask)] = b;
-
-      /* Validate the pngpriv.h hash function. */
-#     define png_chunk_hash lut
-         {
-            unsigned int i;
-
-            for (i=0; i<known_chunk_count; ++i)
-            {
-               png_uint_32 chunk = chunks[i];
-
-               if (PNG_CHUNK_HASH(chunk) != i)
-                  error("internal error: hash didn't work!");
-            }
-         }
-#     undef lut
-
-      /* Print all the results, first the stuff for pngpriv.h */
-      {
-         unsigned int i = 0;
-
-         while (strings[i] != 0)
-            puts(strings[i++]);
-
-         printf("#define PNG_CHUNK_HASH_MASK 0x%lxU\n",
-            (unsigned long)best_mask);
-         printf("#define PNG_CHUNK_HASH_C0 %u\n", best_c[0]);
-         printf("#define PNG_CHUNK_HASH_C1 %u\n", best_c[1]);
-         printf("#define PNG_CHUNK_HASH_C2 %u\n", best_c[2]);
-         printf("#define PNG_CHUNK_HASH_C3 %u\n", best_c[3]);
-
-         /* Print the hash codes of all the chunks */
-         putchar('\n');
-         print_chunks(chunks, known_chunk_count, 0, 0xffffffff, best_c,
-            best_mask, lut);
-         putchar('\n');
-         printf("#define PNG_KNOWN_CHUNK_COUNT %u\n", known_chunk_count);
-
-         while (strings[++i] != 0)
-            puts(strings[i]);
-
-         /* Now print the LUT */
-         fputs("   ", stdout);
-         {
-            unsigned int j;
-
-            for (j=0; j<=best_mask; ++j)
-            {
-               printf("%d", lut[j]);
-
-               if ((j % 16) == 15 && j < best_mask)
-                  printf(",\n   ");
-
-               else if (j < best_mask)
-                  printf(", ");
-
-               else
-                  printf("\n");
-            }
-         }
-
-         /* And the trailing text */
-         while (strings[++i] != 0)
-            puts(strings[i]);
-      }
-   }
-
-   exit(0);
-}
--- a/contrib/tools/chunkhash.h
+++ b/contrib/tools/chunkhash.h
@@ -1,97 +0,0 @@
-/* chunkhash.h -- a perfect hash code for the chunk names in png.h
- *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- *
- * THIS IS A MACHINE GENERATED FILE.  See contrib/tools/chunkhash.c for
- * copyright and other information.
- *
- * USAGE:  To include the PNG_CHUNK_HASH macro and associated definitions:
- *
- * #define PNG_CHUNKHASH_DEFS
- * #include "contrib/tools/chunkhash.h"
- *
- * To define the png_chunk_hash array used by the macro:
- *
- * #define PNG_CHUNKHASH_CODE
- * #include "contrib/tools/chunkhash.h"
- *
- * One or both of the defines must be given except when building chunkhash
- * itself.
- */
-#ifdef PNG_CHUNKHASH_DEFS
-#ifndef PNG_CHUNKHASH_H
-#define PNG_CHUNKHASH_H
-/* A perfect hash code - returns a value 0..(PNG_KNOWN_CHUNK_COUNT-1) and is
- * generated by the ridiculously simple program in contrib/tools/chunkhash.c
- *
- * The hash code used here multiplies each byte by a different constant to
- * return a single number:
- *
- *    b0 * c[0] + b1 * [c1] + b2 * c[2] + b3 * c[3]
- *
- * The values of the constants are found by search using the a table of
- * primes, including 0, and may be (in fact are at present) 0 for some of the
- * bytes, the compiler is expected to optimize multiply by zero, or one!
- *
- * The lookup table reduces the sparse result of the hash calculation to the
- * correct index values.  The chunks are indexed in the string order of the
- * png_uint_32 chunk names.
- */
-#define PNG_CHUNK_HASH_MASK 0x3fU
-#define PNG_CHUNK_HASH_C0 103
-#define PNG_CHUNK_HASH_C1 1
-#define PNG_CHUNK_HASH_C2 0
-#define PNG_CHUNK_HASH_C3 1
-
-#define PNG_CHUNK_IDAT_TAG 0
-#define PNG_CHUNK_IEND_TAG 1
-#define PNG_CHUNK_IHDR_TAG 2
-#define PNG_CHUNK_PLTE_TAG 3
-#define PNG_CHUNK_bKGD_TAG 4
-#define PNG_CHUNK_cHRM_TAG 5
-#define PNG_CHUNK_fRAc_TAG 6
-#define PNG_CHUNK_gAMA_TAG 7
-#define PNG_CHUNK_gIFg_TAG 8
-#define PNG_CHUNK_gIFt_TAG 9
-#define PNG_CHUNK_gIFx_TAG 10
-#define PNG_CHUNK_hIST_TAG 11
-#define PNG_CHUNK_iCCP_TAG 12
-#define PNG_CHUNK_iTXt_TAG 13
-#define PNG_CHUNK_oFFs_TAG 14
-#define PNG_CHUNK_pCAL_TAG 15
-#define PNG_CHUNK_pHYs_TAG 16
-#define PNG_CHUNK_sBIT_TAG 17
-#define PNG_CHUNK_sCAL_TAG 18
-#define PNG_CHUNK_sPLT_TAG 19
-#define PNG_CHUNK_sRGB_TAG 20
-#define PNG_CHUNK_sTER_TAG 21
-#define PNG_CHUNK_tEXt_TAG 22
-#define PNG_CHUNK_tIME_TAG 23
-#define PNG_CHUNK_tRNS_TAG 24
-#define PNG_CHUNK_zTXt_TAG 25
-
-#define PNG_KNOWN_CHUNK_COUNT 26
-
-extern const png_byte png_chunk_hash[PNG_CHUNK_HASH_MASK+1];
-#endif /* !PNG_CHUNKHASH_H */
-#endif /* PNG_CHUNKHASH_DEFS */
-
-#ifndef PNG_CHUNK_HASH
-#define PNG_CHUNK_HASH(chunk) (png_chunk_hash[PNG_CHUNK_HASH_MASK & (\
-      ((chunk) >> 24) * PNG_CHUNK_HASH_C0 +\
-      ((chunk) >> 16) * PNG_CHUNK_HASH_C1 +\
-      ((chunk) >>  8) * PNG_CHUNK_HASH_C2 +\
-      ((chunk)      ) * PNG_CHUNK_HASH_C3)])
-#endif
-
-#ifdef PNG_CHUNKHASH_CODE
-#ifndef PNG_CHUNKHASH_C
-#define PNG_CHUNKHASH_C
-const png_byte png_chunk_hash[PNG_CHUNK_HASH_MASK+1] = {
-   26, 3, 26, 26, 26, 26, 26, 13, 26, 26, 26, 16, 26, 26, 26, 26,
-   26, 24, 12, 26, 18, 26, 26, 26, 26, 20, 26, 17, 26, 26, 25, 15,
-   26, 8, 14, 26, 26, 22, 26, 26, 1, 19, 5, 21, 26, 26, 9, 26,
-   26, 26, 10, 7, 26, 11, 26, 0, 26, 2, 23, 26, 26, 4, 26, 6
-};
-#endif /* !PNG_CHUNKHASH_C */
-#endif /* PNG_CHUNKHASH_CODE */
--- a/contrib/tools/scale.c
+++ b/contrib/tools/scale.c
@@ -1,238 +0,0 @@
-/* Given a target range and a source range work out an expression to scale from
- * the source to the target of the form:
- *
- *    (number * mult + add)>>16
- *
- * The command arguments are:
- *
- *    scale target source
- *
- * and the program works out a pair of numbers, mult and add, that evaluate:
- *
- *          number * target
- *   round( --------------- )
- *              source
- *
- * exactly for number in the range 0..source
- */
-#define _ISOC99_SOURCE 1
-
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-#include <math.h>
-
-static double minerr;
-static unsigned long minmult, minadd, minshift;
-static long mindelta;
-
-static int
-test(unsigned long target, unsigned long source, unsigned long mult,
-   long add, unsigned long shift, long delta)
-{
-   unsigned long i;
-   double maxerr = 0;
-   double rs = (double)target/source;
-
-   for (i=0; i<=source; ++i)
-   {
-      unsigned long t = i*mult+add;
-      double err = fabs((t >> shift) - i*rs);
-
-      if (err > minerr)
-         return 0;
-
-      if (err > maxerr)
-         maxerr = err;
-   }
-
-   if (maxerr < minerr)
-   {
-      minerr = maxerr;
-      minmult = mult;
-      minadd = add;
-      minshift = shift;
-      mindelta = delta;
-   }
-
-   return maxerr < .5;
-}
-
-static int
-dotest(unsigned long target, unsigned long source, unsigned long mult,
-   long add, unsigned long shift, long delta, int print)
-{
-   if (test(target, source, mult, add, shift, delta))
-   {
-      if (print & 4)
-         printf("      {%11lu,%6ld /* >>%lu */ }, /* %lu/%lu */\n",
-            mult, add, shift, target, source);
-
-      else if (print & 2)
-         printf("      {%11lu,%6ld,%3lu }, /* %lu/%lu */\n",
-            mult, add, shift, target, source);
-
-      else if (print)
-         printf("number * %lu/%lu = (number * %lu + %ld) >> %lu [delta %ld]\n",
-            target, source, mult, add, shift, delta);
-
-      return 1;
-   }
-
-   return 0;
-}
-
-static int
-find(unsigned long target, unsigned long source, int print, int fixshift)
-{
-   unsigned long shift = 0;
-   unsigned long shiftlim = 0;
-
-   /* In the final math the sum is at most (source*mult+add) >> shift, so:
-    *
-    *    source*mult+add < 1<<32
-    *    mult < (1<<32)/source
-    *
-    * but:
-    *
-    *    mult = (target<<shift)/source
-    *
-    * so:
-    *
-    *    (target<<shift) < (1<<32)
-    */
-   if (fixshift < 0)
-      while ((target<<shiftlim) < 0x80000000U) ++shiftlim;
-
-   else
-      shift = shiftlim = (unsigned long)fixshift;
-
-   minerr = 1E8;
-
-   for (; shift<=shiftlim; ++shift)
-   {
-      unsigned long mult = ((target<<shift) + (source>>1)) / source;
-      long delta;
-      long limit = 1; /* seems to be sufficient */
-      long add, start, end;
-
-      end = 1<<shift;
-      start = -end;
-
-      for (add=start; add<=end; ++add)
-         if (dotest(target,source,mult,add,shift,0,print))
-            return 1;
-
-      for (delta=1; delta<=limit; ++delta)
-      {
-#        if 0
-            fprintf(stderr, "%lu/%lu: shift %lu, delta %lu\n", target, source,
-               shift, delta);
-#        endif
-
-         for (add=start; add<=end; ++add)
-         {
-            if (dotest(target, source, mult-delta, add, shift, -delta, print))
-               return 1;
-
-            if (dotest(target, source, mult+delta, add, shift, delta, print))
-               return 1;
-         }
-      }
-   }
-
-   if (print & 4)
-      printf("      {%11lu,%6ld /* >>%lu */ }, /* %lu/%lu ERROR: .5+%g*/\n",
-         minmult, minadd, minshift, target, source, minerr-.5);
-
-   else if (print & 2)
-      printf("      {%11lu,%6ld,%3lu }, /* %lu/%lu ERROR: .5+%g*/\n",
-         minmult, minadd, minshift, target, source, minerr-.5);
-
-   else if (print)
-      printf(
-         "number * %lu/%lu ~= (number * %lu + %ld) >> %lu +/-.5+%g [delta %ld]\n",
-         target, source, minmult, minadd, minshift, minerr-.5, mindelta);
-
-   return 0;
-}
-
-static void
-usage(const char *prog)
-{
-   fprintf(stderr,
-      "usage: %s {--denominator|--maxshift|--code} target {source}\n"
-      " For each 'source' prints 'mult' and 'add' such that:\n\n"
-      "   (number * mult + add) >> 16 = round(number*target/source)\n\n"
-      " for all integer values of number in the range 0..source.\n\n"
-      " --denominator: swap target and source (specify a single source first\n"
-      "                and follow with multiple targets.)\n"
-      "    --maxshift: find the lowest shift value that works for all the\n"
-      "                repeated 'source' values\n"
-      "        --code: output C code for array/structure initialization\n",
-      prog);
-   exit(1);
-}
-
-int
-main(int argc, const char **argv)
-{
-   int i, err = 0, maxshift = 0, firstsrc = 1, code = 0, denominator = 0;
-   unsigned long target, shift = 0;
-
-   while (argc > 1)
-   {
-      if (strcmp(argv[firstsrc], "--maxshift") == 0)
-      {
-         maxshift = 1;
-         ++firstsrc;
-      }
-
-      else if (strcmp(argv[firstsrc], "--code") == 0)
-      {
-         code = 1;
-         ++firstsrc;
-      }
-
-      else if (strcmp(argv[firstsrc], "--denominator") == 0)
-      {
-         denominator = 1;
-         ++firstsrc;
-      }
-
-      else
-         break;
-   }
-
-
-   if (argc < 2+firstsrc)
-      usage(argv[0]);
-
-   target = strtoul(argv[firstsrc++], 0, 0);
-   if (target == 0) usage(argv[0]);
-
-   for (i=firstsrc; i<argc; ++i)
-   {
-      unsigned long source = strtoul(argv[i], 0, 0);
-
-      if (source == 0) usage(argv[0]);
-
-      if (!find(denominator ? source : target, denominator ? target : source,
-         maxshift ? 0 : 1+code, -1))
-         err = 1;
-
-      if (minshift > shift) shift = minshift;
-   }
-
-   if (maxshift) for (i=firstsrc; i<argc; ++i)
-   {
-      unsigned long source = strtoul(argv[i], 0, 0);
-
-      if (!find(denominator ? source : target, denominator ? target : source,
-         code ? 4 : 1, shift))
-         err = 1;
-   }
-
-   /* Just an exit code - the printout above lists the problem */
-   return err;
-}
--- a/example.c
+++ b/example.c
@@ -2,7 +2,7 @@
 #if 0 /* in case someone actually tries to compile this */

 /* example.c - an example of using libpng
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.11 [(PENDING RELEASE)]
 * Maintained 1998-2014 Glenn Randers-Pehrson
 * Maintained 1996, 1997 Andreas Dilger)
 * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -39,7 +39,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <png.h>
-#include PNG_ZLIB_HEADER /* this is the header libpng was built with */
+#include <zlib.h>

 int main(int argc, const char **argv)
 {
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1,6 +1,6 @@
 libpng-manual.txt - A description on how to use and modify libpng

- libpng version 1.7.0beta34 - March 17, 2014
+ libpng version 1.6.11beta02 - April 6, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2014 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.7.0beta34 - March 17, 2014
+ libpng versions 0.97, January 1998, through 1.6.11beta02 - April 6, 2014
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2014 Glenn Randers-Pehrson

@@ -42,11 +42,10 @@ libpng-manual.txt - A description on how to use and modify libpng
    X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
   XI. Changes to Libpng from version 1.4.x to 1.5.x
  XII. Changes to Libpng from version 1.5.x to 1.6.x
- XIII. Changes to Libpng from version 1.6.x to 1.7.x
-  XIV. Detecting libpng
-   XV. Source code repository
-  XVI. Coding style
- XVII. Y2K Compliance in libpng
+ XIII. Detecting libpng
+  XIV. Source code repository
+   XV. Coding style
+  XVI. Y2K Compliance in libpng

 I. Introduction

@@ -428,9 +427,9 @@ an end_info structure.

 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT which defaults to abort().
+errors will result in a call to PNG_ABORT() which defaults to abort().

-You can #define PNG_ABORT to a function or other C code that does something
+You can #define PNG_ABORT() to a function that does something
 more useful than abort(), as long as your function does not
 return.

@@ -525,15 +524,15 @@ you can retrieve with

    png_get_user_chunk_ptr(png_ptr);

-If you call the png_set_read_user_chunk_fn() function, then all unknown chunks
-will be passed to your callback when read.  You can cause known chunks to be
-passed in as well by using png_set_keep_unknown_chunks (see below) - this will
-prevent the normal libpng handling of those known chunks.
-
-If your callback returns 0 the default unknown handling will be used (see
-below).  This is new behavior in libpng 1.7, prior to 1.7 it was not possible to
-discard a chunk; PNG_HANDLE_CHUNK_IF_SAFE was forced.  Libpng 1.6.0 issues a
-warning when this was done.
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks which the callback does not handle will be saved when read.  You can
+cause them to be discarded by returning '1' ("handled") instead of '0'.  This
+behavior will change in libpng 1.7 and the default handling set by the
+png_set_keep_unknown_chunks() function, described below, will be used when the
+callback returns 0.  If you want the existing behavior you should set the global
+default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
+versions of libpng and with 1.7.  Libpng 1.6 issues a warning if you keep the
+default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.

 At this point, you can set up a callback function that will be
 called after each row has been read, which you can use to control
@@ -632,8 +631,10 @@ callback function:
    ...

    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-      /* ignore all unknown chunks: */
-      png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
+      /* ignore all unknown chunks
+       * (use global setting "2" for libpng16 and earlier):
+       */
+      png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);

      /* except for vpAg: */
      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
@@ -2738,10 +2739,11 @@ section below for more information on the libpng error handling.

 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT which defaults to abort().
+errors will result in a call to PNG_ABORT() which defaults to abort().

-You can #define PNG_ABORT to a function or other C code that does something
-more useful than abort(), as long as your function does not return.
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.

 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
@@ -4159,7 +4161,7 @@ Error handling in libpng is done through png_error() and png_warning().
 Errors handled through png_error() are fatal, meaning that png_error()
 should never return to its caller.  Currently, this is handled via
 setjmp() and longjmp() (unless you have compiled libpng with
-PNG_NO_SETJMP, in which case it is handled via PNG_ABORT),
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
 but you could change this to do things like exit() if you should wish,
 as long as your function does not return.

@@ -4291,6 +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
@@ -4752,8 +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,
@@ -5090,40 +5092,7 @@ length, which resulted in PNG files that cannot be read beyond the bad iTXt
 chunk.  This error was fixed in libpng-1.6.3, and a tool (called
 contrib/tools/png-fix-itxt) has been added to the libpng distribution.

-XIII.  Changes to Libpng from version 1.6.x to 1.7.x
-
-Some functions that were deprecated in libpng-1.6.0 were removed:
-    png_reset_zstream(),
-    png_info_init_3(),
-    png_data_freer() and its associated flags,
-    png_malloc_default(),
-    and png_free_default().
-
-The PNG_ABORT() macro was changed to PNG_ABORT, and the default is now
-"abort()" for all platforms (previously it was "ExitProcess(0)" on
-Windows platforms).  Starting with libpng-1.7.0 you have to define
-PNG_ABORT instead of PNG_ABORT(), and you must include a terminating
-semicolon in your definition, e.g.,
-
-    #if PNGCRUSH_LIBPNG_VER >= 10700
-    #  ifdef _WINDOWS_
-    #    define PNG_ABORT ExitProcess(0);
-    #  else
-    #    define PNG_ABORT abort();
-    #  endif
-    #else
-    #  ifdef _WINDOWS_
-    #    define PNG_ABORT() ExitProcess(0)
-    #  else
-    #    define PNG_ABORT() abort()
-    #  endif
-    #endif
-
-The 8-bit compose and rgb_to_grayscale operations were made more accurate.
-While these did not introduce API incompatibility, there may be differences
-in unit test results.
-
-XIV.  Detecting libpng
+XIII.  Detecting libpng

 The png_get_io_ptr() function has been present since libpng-0.88, has never
 changed, and is unaffected by conditional compilation macros.  It is the
@@ -5156,9 +5125,10 @@ simple verbal discriptions of bug fixes, reported either to the
 SourceForge bug tracker, to the png-mng-implement at lists.sf.net
 mailing list, or directly to glennrp.

-XVI. Coding style
+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)
@@ -5289,15 +5259,15 @@ Lines do not exceed 80 characters.

 Other rules can be inferred by inspecting the libpng source.

-XVII. Y2K Compliance in libpng
+XVI. Y2K Compliance in libpng

-March 17, 2014
+April 6, 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 1.7.0beta34 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.11beta02 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
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "March 17, 2014"
+.TH LIBPNG 3 "April 6, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta34
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.11beta02
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -23,7 +23,7 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta34

 \fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP

-\fBpng_charp png_convert_to_rfc1123_buffer (png_structp \fP\fIpng_ptr\fP\fB, char \fP\fIout[29]\fP\fB, png_timep \fIptime\fP\fB);\fP
+\fBpng_charp png_convert_to_rfc1123 (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fIptime\fP\fB);\fP

 \fBpng_infop png_create_info_struct (png_structp \fIpng_ptr\fP\fB);\fP

@@ -35,6 +35,8 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta34

 \fBpng_structp png_create_write_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP

+\fBvoid png_data_freer (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIfreer\fP\fB, png_uint_32 \fImask)\fP\fB);\fP
+
 \fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP

 \fBvoid png_destroy_read_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fP\fIinfo_ptr_ptr\fP\fB, png_infopp \fIend_info_ptr_ptr\fP\fB);\fP
@@ -49,6 +51,8 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta34

 \fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP

+\fBvoid png_free_default (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
+
 \fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP

 \fBpng_byte png_get_bit_depth (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
@@ -225,12 +229,16 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta34

 \fBint png_image_write_to_stdio (png_imagep \fP\fIimage\fP\fB, FILE \fP\fI*file\fP\fB, int \fP\fIconvert_to_8_bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap)\fP\fB);\fP

+\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, png_size_t \fIpng_info_struct_size\fP\fB);\fP
+
 \fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP

 \fBvoid png_longjmp (png_structp \fP\fIpng_ptr\fP\fB, int \fIval\fP\fB);\fP

 \fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP

+\fBpng_voidp png_malloc_default (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
 \fBpng_voidp png_malloc_warn (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP

 \fBpng_uint_32 png_permit_mng_features (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fImng_features_permitted\fP\fB);\fP
@@ -257,6 +265,8 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta34

 \fBvoid png_read_update_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP

+\fBint png_reset_zstream (png_structp \fIpng_ptr\fP\fB);\fP
+
 \fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP

 \fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP
@@ -494,7 +504,7 @@ 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 1.7.0beta34 - March 17, 2014
+ libpng version 1.6.11beta02 - April 6, 2014
 Updated and distributed by Glenn Randers-Pehrson
 <glennrp at users.sourceforge.net>
 Copyright (c) 1998-2014 Glenn Randers-Pehrson
@@ -505,7 +515,7 @@ libpng-manual.txt - A description on how to use and modify libpng

 Based on:

- libpng versions 0.97, January 1998, through 1.7.0beta34 - March 17, 2014
+ libpng versions 0.97, January 1998, through 1.6.11beta02 - April 6, 2014
 Updated and distributed by Glenn Randers-Pehrson
 Copyright (c) 1998-2014 Glenn Randers-Pehrson

@@ -536,11 +546,10 @@ libpng-manual.txt - A description on how to use and modify libpng
    X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
   XI. Changes to Libpng from version 1.4.x to 1.5.x
  XII. Changes to Libpng from version 1.5.x to 1.6.x
- XIII. Changes to Libpng from version 1.6.x to 1.7.x
-  XIV. Detecting libpng
-   XV. Source code repository
-  XVI. Coding style
- XVII. Y2K Compliance in libpng
+ XIII. Detecting libpng
+  XIV. Source code repository
+   XV. Coding style
+  XVI. Y2K Compliance in libpng

 .SH I. Introduction

@@ -922,9 +931,9 @@ an end_info structure.

 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT which defaults to abort().
+errors will result in a call to PNG_ABORT() which defaults to abort().

-You can #define PNG_ABORT to a function or other C code that does something
+You can #define PNG_ABORT() to a function that does something
 more useful than abort(), as long as your function does not
 return.

@@ -1019,15 +1028,15 @@ you can retrieve with

    png_get_user_chunk_ptr(png_ptr);

-If you call the png_set_read_user_chunk_fn() function, then all unknown chunks
-will be passed to your callback when read.  You can cause known chunks to be
-passed in as well by using png_set_keep_unknown_chunks (see below) - this will
-prevent the normal libpng handling of those known chunks.
-
-If your callback returns 0 the default unknown handling will be used (see
-below).  This is new behavior in libpng 1.7, prior to 1.7 it was not possible to
-discard a chunk; PNG_HANDLE_CHUNK_IF_SAFE was forced.  Libpng 1.6.0 issues a
-warning when this was done.
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks which the callback does not handle will be saved when read.  You can
+cause them to be discarded by returning '1' ("handled") instead of '0'.  This
+behavior will change in libpng 1.7 and the default handling set by the
+png_set_keep_unknown_chunks() function, described below, will be used when the
+callback returns 0.  If you want the existing behavior you should set the global
+default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
+versions of libpng and with 1.7.  Libpng 1.6 issues a warning if you keep the
+default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.

 At this point, you can set up a callback function that will be
 called after each row has been read, which you can use to control
@@ -1126,8 +1135,10 @@ callback function:
    ...

    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-      /* ignore all unknown chunks: */
-      png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
+      /* ignore all unknown chunks
+       * (use global setting "2" for libpng16 and earlier):
+       */
+      png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);

      /* except for vpAg: */
      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
@@ -3232,10 +3243,11 @@ section below for more information on the libpng error handling.

 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT which defaults to abort().
+errors will result in a call to PNG_ABORT() which defaults to abort().

-You can #define PNG_ABORT to a function or other C code that does something
-more useful than abort(), as long as your function does not return.
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.

 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
@@ -4653,7 +4665,7 @@ Error handling in libpng is done through png_error() and png_warning().
 Errors handled through png_error() are fatal, meaning that png_error()
 should never return to its caller.  Currently, this is handled via
 setjmp() and longjmp() (unless you have compiled libpng with
-PNG_NO_SETJMP, in which case it is handled via PNG_ABORT),
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
 but you could change this to do things like exit() if you should wish,
 as long as your function does not return.

@@ -4785,6 +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
@@ -5246,8 +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,
@@ -5584,40 +5596,7 @@ length, which resulted in PNG files that cannot be read beyond the bad iTXt
 chunk.  This error was fixed in libpng-1.6.3, and a tool (called
 contrib/tools/png-fix-itxt) has been added to the libpng distribution.

-.SH XIII.  Changes to Libpng from version 1.6.x to 1.7.x
-
-Some functions that were deprecated in libpng-1.6.0 were removed:
-    png_reset_zstream(),
-    png_info_init_3(),
-    png_data_freer() and its associated flags,
-    png_malloc_default(),
-    and png_free_default().
-
-The PNG_ABORT() macro was changed to PNG_ABORT, and the default is now
-"abort()" for all platforms (previously it was "ExitProcess(0)" on
-Windows platforms).  Starting with libpng-1.7.0 you have to define
-PNG_ABORT instead of PNG_ABORT(), and you must include a terminating
-semicolon in your definition, e.g.,
-
-    #if PNGCRUSH_LIBPNG_VER >= 10700
-    #  ifdef _WINDOWS_
-    #    define PNG_ABORT ExitProcess(0);
-    #  else
-    #    define PNG_ABORT abort();
-    #  endif
-    #else
-    #  ifdef _WINDOWS_
-    #    define PNG_ABORT() ExitProcess(0)
-    #  else
-    #    define PNG_ABORT() abort()
-    #  endif
-    #endif
-
-The 8-bit compose and rgb_to_grayscale operations were made more accurate.
-While these did not introduce API incompatibility, there may be differences
-in unit test results.
-
-.SH XIV.  Detecting libpng
+.SH XIII.  Detecting libpng

 The png_get_io_ptr() function has been present since libpng-0.88, has never
 changed, and is unaffected by conditional compilation macros.  It is the
@@ -5650,9 +5629,10 @@ simple verbal discriptions of bug fixes, reported either to the
 SourceForge bug tracker, to the png-mng-implement at lists.sf.net
 mailing list, or directly to glennrp.

-.SH XVI. Coding style
+.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)
@@ -5783,15 +5763,15 @@ Lines do not exceed 80 characters.

 Other rules can be inferred by inspecting the libpng source.

-.SH XVII. Y2K Compliance in libpng
+.SH XVI. Y2K Compliance in libpng

-March 17, 2014
+April 6, 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 1.7.0beta34 are Y2K compliant.  It is my belief that earlier
+upward through 1.6.11beta02 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
@@ -5996,9 +5976,36 @@ the first widely used release:
 1.5.7beta01-05      15    10507  15.so.15.7[.0]
 1.5.7rc01-03        15    10507  15.so.15.7[.0]
 1.5.7               15    10507  15.so.15.7[.0]
- 1.6.0beta01-37      16    10600  16.so.16.0[.0]
- 1.7.0alpha01-10     17    10700  17.so.17.0[.0]
- 1.7.0beta01-34      17    10700  17.so.17.0[.0]
+ 1.6.0beta01-40      16    10600  16.so.16.0[.0]
+ 1.6.0rc01-08        16    10600  16.so.16.0[.0]
+ 1.6.0               16    10600  16.so.16.0[.0]
+ 1.6.1beta01-09      16    10601  16.so.16.1[.0]
+ 1.6.1rc01           16    10601  16.so.16.1[.0]
+ 1.6.1               16    10601  16.so.16.1[.0]
+ 1.6.2beta01         16    10602  16.so.16.2[.0]
+ 1.6.2rc01-06        16    10602  16.so.16.2[.0]
+ 1.6.2               16    10602  16.so.16.2[.0]
+ 1.6.3beta01-11      16    10603  16.so.16.3[.0]
+ 1.6.3rc01           16    10603  16.so.16.3[.0]
+ 1.6.3               16    10603  16.so.16.3[.0]
+ 1.6.4beta01-02      16    10604  16.so.16.4[.0]
+ 1.6.4rc01           16    10604  16.so.16.4[.0]
+ 1.6.4               16    10604  16.so.16.4[.0]
+ 1.6.5               16    10605  16.so.16.5[.0]
+ 1.6.6               16    10606  16.so.16.6[.0]
+ 1.6.7beta01-04      16    10607  16.so.16.7[.0]
+ 1.6.7rc01-02        16    10607  16.so.16.7[.0]
+ 1.6.7               16    10607  16.so.16.7[.0]
+ 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]
+ 1.6.9beta01-04      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]
+ 1.6.11beta01-02     16    10611  16.so.16.11[.0]

 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6055,7 +6062,7 @@ possible without all of you.

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

-Libpng version 1.7.0beta34 - March 17, 2014:
+Libpng version 1.6.11beta02 - April 6, 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).

@@ -6078,7 +6085,7 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.7.0beta34, March 17, 2014, are
+libpng versions 1.2.6, August 15, 2004, through 1.6.11beta02, April 6, 2014, are
 Copyright (c) 2004,2006-2007 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
@@ -6177,7 +6184,7 @@ certification mark of the Open Source Initiative.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-March 17, 2014
+April 6, 2014

 .\" end of man page

--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "March 17, 2014"
+.TH LIBPNGPF 3 "April 6, 2014"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta34
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.11beta02
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "March 17, 2014"
+.TH PNG 5 "April 6, 2014"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
@@ -24,7 +24,6 @@ PNG specification (second edition), November 2003:
 .IP
 .br
  <http://www.w3.org/TR/2003/REC-PNG-20031110/
-.LP
 PNG 1.2 specification, July 1999:
 .IP
 .br
@@ -59,7 +58,7 @@ Thomas Boutell and others (png-list).

 .SH COPYRIGHT NOTICE
 .LP
-This man page is Copyright (c) 1998-2012 Glenn Randers-Pehrson.  See png.h
+This man page is Copyright (c) 1998-2006 Glenn Randers-Pehrson.  See png.h
 for conditions of use and distribution.
 .LP
 The PNG Specification (Second Edition) is
--- 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 1.7.0beta34 - March 17, 2014
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * libpng version 1.6.11beta02 - April 6, 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 1.7.0beta34 - March 17, 2014: Glenn
+ *   libpng versions 0.97, January 1998, through 1.6.11beta02 - April 6, 2014: Glenn
 *   See also "Contributing Authors", below.
 *
 * Note about libpng version numbers:
@@ -166,9 +166,36 @@
 *    1.5.7beta01-05          15    10507  15.so.15.7[.0]
 *    1.5.7rc01-03            15    10507  15.so.15.7[.0]
 *    1.5.7                   15    10507  15.so.15.7[.0]
- *    1.6.0beta01-37          16    10600  16.so.16.0[.0]
- *    1.7.0alpha01-10         17    10700  17.so.17.0[.0]
- *    1.7.0beta01-34          17    10700  17.so.17.0[.0]
+ *    1.6.0beta01-40          16    10600  16.so.16.0[.0]
+ *    1.6.0rc01-08            16    10600  16.so.16.0[.0]
+ *    1.6.0                   16    10600  16.so.16.0[.0]
+ *    1.6.1beta01-09          16    10601  16.so.16.1[.0]
+ *    1.6.1rc01               16    10601  16.so.16.1[.0]
+ *    1.6.1                   16    10601  16.so.16.1[.0]
+ *    1.6.2beta01             16    10602  16.so.16.2[.0]
+ *    1.6.2rc01-06            16    10602  16.so.16.2[.0]
+ *    1.6.2                   16    10602  16.so.16.2[.0]
+ *    1.6.3beta01-11          16    10603  16.so.16.3[.0]
+ *    1.6.3rc01               16    10603  16.so.16.3[.0]
+ *    1.6.3                   16    10603  16.so.16.3[.0]
+ *    1.6.4beta01-02          16    10604  16.so.16.4[.0]
+ *    1.6.4rc01               16    10604  16.so.16.4[.0]
+ *    1.6.4                   16    10604  16.so.16.4[.0]
+ *    1.6.5                   16    10605  16.so.16.5[.0]
+ *    1.6.6                   16    10606  16.so.16.6[.0]
+ *    1.6.7beta01-04          16    10607  16.so.16.7[.0]
+ *    1.6.7rc01-03            16    10607  16.so.16.7[.0]
+ *    1.6.7                   16    10607  16.so.16.7[.0]
+ *    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]
+ *    1.6.9beta01-04          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]
+ *    1.6.11beta01-02         16    10611  16.so.16.11[.0]
 *
 *   Henceforth the source version will match the shared-library major
 *   and minor numbers; the shared-library major version number will be
@@ -200,7 +227,7 @@
 *
 * This code is released under the libpng license.
 *
- * libpng versions 1.2.6, August 15, 2004, through 1.7.0beta34, March 17, 2014, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.6.11beta02, April 6, 2014, are
 * Copyright (c) 2004, 2006-2013 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:
@@ -312,13 +339,13 @@
 * Y2K compliance in libpng:
 * =========================
 *
- *    March 17, 2014
+ *    April 6, 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 1.7.0beta34 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.11beta02 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
@@ -371,30 +398,32 @@
 /* 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 "1.7.0beta34"
+#define PNG_LIBPNG_VER_STRING "1.6.11beta02"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.7.0beta34 - March 17, 2014\n"
+     " libpng version 1.6.11beta02 - April 6, 2014\n"

-#define PNG_LIBPNG_VER_SONUM   17
-#define PNG_LIBPNG_VER_DLLNUM  17
+#define PNG_LIBPNG_VER_SONUM   16
+#define PNG_LIBPNG_VER_DLLNUM  16

 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
-#define PNG_LIBPNG_VER_MINOR   7
-#define PNG_LIBPNG_VER_RELEASE 0
+#define PNG_LIBPNG_VER_MINOR   6
+#define PNG_LIBPNG_VER_RELEASE 11

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

-#define PNG_LIBPNG_VER_BUILD  34
+#define PNG_LIBPNG_VER_BUILD  02

 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -419,7 +448,7 @@
 * 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 10700 /* 1.7.0 */
+#define PNG_LIBPNG_VER 10611 /* 1.6.11 */

 /* Library configuration: these options cannot be changed after
 * the library has been built.
@@ -464,6 +493,11 @@

 #ifndef PNG_VERSION_INFO_ONLY

+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
 /* Version information for C files, stored in png.c.  This had better match
 * the version above.
 */
@@ -471,138 +505,17 @@

 /* This file is arranged in several sections:
 *
- * 1. ISO-PNG constants and definitions; values defined by PNG and not specific
- *    to the libpng API.
- * 2. Any configuration options that can be specified by for the application
+ * 1. Any configuration options that can be specified by for the application
 *    code when it is built.  (Build time configuration is in pnglibconf.h)
- * 3. Type definitions (base types are defined in pngconf.h), structure
+ * 2. Type definitions (base types are defined in pngconf.h), structure
 *    definitions.
- * 4. Exported library functions.
- * 5. Simplified API.
+ * 3. Exported library functions.
+ * 4. Simplified API.
 *
 * The library source code has additional files (principally pngpriv.h) that
 * allow configuration of the library.
 */
-
-/* Section 1: ISO PNG constants and macros. */
-
-/* ISO-PNG defines byte encodings for 16 and 32-bit unsigned values and 32-bit
- * signed values.  The macros PNG_U16, PNG_U32 and PNG_S32 return values of type
- * (png_uint_16), (png_uint_32) and (png_int_32) which are target machine
- * specific representations of these values, using the types defined in
- * pngconf.h.  The macros take two or four byte values in the order in which
- * they would occur in a PNG stream.
- *
- * These macros must return compile time constants if passed constant values -
- * machine specific implementations are not permitted.  These macros are used by
- * default in the API functions/macros png_get_uint_16, png_get_uint_32,
- * png_get_uint_31 and png_get_int_32 declared below: these functions or macros
- * are the correct places for machine specific implementations (such as hardware
- * specific instructions.)
- *
- * The macros defined here are generic and intended to give maximum flexibility
- * in implementation to the compiler; only PNG_S32 contains a sequence point,
- * there are no side effects and the expressions used permit the maximum
- * parallelization (relevant because the four bytes may be loaded in parallel.)
- */
-#define PNG_u2(b1, b2) (((unsigned int)(b1) << 8) + (b2))
-
-#define PNG_U16(b1, b2) ((png_uint_16)PNG_u2(b1, b2))
-#define PNG_U32(b1, b2, b3, b4)\
-   (((png_uint_32)PNG_u2(b1, b2) << 16) + PNG_u2(b3, b4))
-
-/* ISO-PNG states that signed 32-bit values are stored in two's complement
- * format.  There is no guarantee that (png_int_32) is exactly 32 bits, so the
- * following macro tests for a negative number and generates the machine format
- * directly by portable arithmetic operations.  The cost is that the argument
- * 'b1' is evaluated twice.
- */
-#define PNG_S32(b1, b2, b3, b4) ((b1) & 0x80\
-      ? -(png_int_32)((PNG_U32(b1, b2, b3, b4) ^ 0xffffffff) + 1)\
-      : (png_int_32)PNG_U32(b1, b2, b3, b4))
-
-/* Constants for known chunk types.
- *
- * MAINTAINERS: If you need to add a chunk, define the name here.
- * For historical reasons these constants have the form png_<name>; i.e.
- * the prefix is lower case.  Please use decimal values as the parameters to
- * match the ISO PNG specification and to avoid relying on the C locale
- * interpretation of character values.  Please keep the list sorted.
- *
- * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
- * type.  In fact the specification does not express chunk types this way,
- * however using a 32-bit value means that the chunk type can be read from the
- * stream using exactly the same code as used for a 32-bit unsigned value and
- * can be examined far more efficiently (using one arithmetic compare).
- *
- * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
- * libpng API still uses strings for 'unknown' chunks and a macro,
- * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
- * that for portable code numeric values must still be used; the string "IHDR"
- * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
- *
- * In 1.7.0 the definitions were made public in png.h to avoid having to
- * duplicate the same definitions in application code.
- *
- * SOURCE: http://www.libpng.org/pub/png/spec/register/
- *    "Register of PNG Public Chunks and Keywords, version 1.4.6"
- *    "Extensions to the PNG Specification, version 1.4.0"
- */
-#define png_IDAT PNG_U32( 73,  68,  65,  84)
-#define png_IEND PNG_U32( 73,  69,  78,  68)
-#define png_IHDR PNG_U32( 73,  72,  68,  82)
-#define png_PLTE PNG_U32( 80,  76,  84,  69)
-#define png_bKGD PNG_U32( 98,  75,  71,  68)
-#define png_cHRM PNG_U32( 99,  72,  82,  77)
-#define png_dSIG PNG_U32(100,  83,  73,  71) /* separate spec */
-#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
-#define png_gAMA PNG_U32(103,  65,  77,  65)
-#define png_gIFg PNG_U32(103,  73,  70, 103)
-#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
-#define png_gIFx PNG_U32(103,  73,  70, 120)
-#define png_hIST PNG_U32(104,  73,  83,  84)
-#define png_iCCP PNG_U32(105,  67,  67,  80)
-#define png_iTXt PNG_U32(105,  84,  88, 116)
-#define png_oFFs PNG_U32(111,  70,  70, 115)
-#define png_pCAL PNG_U32(112,  67,  65,  76)
-#define png_pHYs PNG_U32(112,  72,  89, 115)
-#define png_sBIT PNG_U32(115,  66,  73,  84)
-#define png_sCAL PNG_U32(115,  67,  65,  76)
-#define png_sPLT PNG_U32(115,  80,  76,  84)
-#define png_sRGB PNG_U32(115,  82,  71,  66)
-#define png_sTER PNG_U32(115,  84,  69,  82)
-#define png_tEXt PNG_U32(116,  69,  88, 116)
-#define png_tIME PNG_U32(116,  73,  77,  69)
-#define png_tRNS PNG_U32(116,  82,  78,  83)
-#define png_zTXt PNG_U32(122,  84,  88, 116)
-
-/* The following will work on (signed char*) strings, whereas the PNG_U32 macro
- * used directory would fail on top-bit-set values because of the sign
- * extension.
- */
-#define PNG_CHUNK_FROM_STRING(s)\
-   PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
-
-/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
- * signed and the argument is a (char[])  This macro will fail miserably on
- * systems where (char) is more than 8 bits.
- */
-#define PNG_STRING_FROM_CHUNK(s,c)\
-   (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
-   ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
-
-/* Do the same but terminate with a null character. */
-#define PNG_CSTRING_FROM_CHUNK(s,c)\
-   (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
-
-/* Test on flag values as defined in the spec (section 5.4): */
-#define PNG_CHUNK_ANCILLARY(c)    (1 & ((c) >> 29))
-#define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
-#define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
-#define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
-#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
-
-/* Section 2: run time configuration
+/* Section 1: run time configuration
 * See pnglibconf.h for build time configuration
 *
 * Run time configuration allows the application to choose between
@@ -632,12 +545,7 @@
 * Otherwise the calls are mapped to png_error.
 */

-/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-
-/* Section 3: type definitions, including structures and compile time
+/* Section 2: type definitions, including structures and compile time
 * constants.
 * See pngconf.h for base types that vary by machine/system
 */
@@ -645,7 +553,7 @@ 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_7_0beta34;
+typedef char* png_libpng_version_1_6_11beta02;

 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
 *
@@ -786,8 +694,8 @@ typedef struct png_text_struct
   png_charp key;          /* keyword, 1-79 character description of "text" */
   png_charp text;         /* comment, may be an empty string (ie "")
                              or a NULL pointer */
-   size_t text_length; /* length of the text string */
-   size_t itxt_length; /* length of the itxt string */
+   png_size_t text_length; /* length of the text string */
+   png_size_t itxt_length; /* length of the itxt string */
   png_charp lang;         /* language code, 0-79 characters
                              or a NULL pointer */
   png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
@@ -840,7 +748,7 @@ typedef struct png_unknown_chunk_t
 {
    png_byte name[5]; /* Textual chunk name with '\0' terminator */
    png_byte *data;   /* Data, should not be modified on read! */
-    size_t size;
+    png_size_t size;

    /* On write 'location' must be set using the flag values listed below.
     * Notice that on read it is set by libpng however the values stored have
@@ -865,7 +773,7 @@ typedef png_unknown_chunk * * png_unknown_chunkpp;
 /* Maximum positive integer used in PNG is (2^31)-1 */
 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
-#define PNG_SIZE_MAX ((size_t)(-1))
+#define PNG_SIZE_MAX ((png_size_t)(-1))

 /* These are constants for fixed point values encoded in the
 * PNG specification manner (x100000)
@@ -970,7 +878,7 @@ typedef png_unknown_chunk * * png_unknown_chunkpp;
 typedef struct png_row_info_struct
 {
   png_uint_32 width;    /* width of row */
-   size_t rowbytes;  /* number of bytes in row */
+   png_size_t rowbytes;  /* number of bytes in row */
   png_byte color_type;  /* color type of row */
   png_byte bit_depth;   /* bit depth of row */
   png_byte channels;    /* number of channels (1, 2, 3, or 4) */
@@ -989,7 +897,7 @@ typedef png_row_info * * png_row_infopp;
 * expected to return the read data in the buffer.
 */
 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
-typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
+typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
    int));
@@ -1082,7 +990,7 @@ typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
    png_alloc_size_t));
 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));

-/* Section 4: exported functions
+/* Section 3: exported functions
 * Here are the function definitions most commonly used.  This is not
 * the place to find out how to use libpng.  See libpng-manual.txt for the
 * full explanation, see example.c for the summary.  This just provides
@@ -1124,8 +1032,8 @@ PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
 * signature, and non-zero otherwise.  Having num_to_check == 0 or
 * start > 7 will always fail (ie return non-zero).
 */
-PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start,
-    size_t num_to_check));
+PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
+    png_size_t num_to_check));

 /* Simple signature checking function.  This is the same as calling
 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
@@ -1144,11 +1052,11 @@ PNG_EXPORTA(5, png_structp, png_create_write_struct,
    png_error_ptr warn_fn),
    PNG_ALLOCATED);

-PNG_EXPORT(6, size_t, png_get_compression_buffer_size,
+PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
    (png_const_structrp png_ptr));

 PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
-    size_t size));
+    png_size_t size));

 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
 * match up.
@@ -1178,8 +1086,8 @@ PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
    PNG_NORETURN);

 #ifdef PNG_READ_SUPPORTED
-/* Reset the compression stream -- Removed from libpng-1.7.0 */
-PNG_REMOVED(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED)
+/* Reset the compression stream */
+PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
 #endif

 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
@@ -1201,7 +1109,7 @@ PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));

 /* Write a PNG chunk - size, type, (optional) data, CRC. */
 PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
-    chunk_name, png_const_bytep data, size_t length));
+    chunk_name, png_const_bytep data, png_size_t length));

 /* Write the start of a PNG chunk - length and chunk name. */
 PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
@@ -1209,7 +1117,7 @@ PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,

 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
 PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
-    png_const_bytep data, size_t length));
+    png_const_bytep data, png_size_t length));

 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
 PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
@@ -1218,9 +1126,12 @@ PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
 PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
    PNG_ALLOCATED);

-/* Removed from libpng-1.7.0 */
-PNG_REMOVED(19, void, png_info_init_3, (png_infopp info_ptr,
-    size_t png_info_struct_size), PNG_DEPRECATED)
+/* DEPRECATED: this function allowed init structures to be created using the
+ * default allocation method (typically malloc).  Use is deprecated in 1.6.0 and
+ * the API will be removed in the future.
+ */
+PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
+    png_size_t png_info_struct_size), PNG_DEPRECATED);

 /* Writes all the PNG information before the image. */
 PNG_EXPORT(20, void, png_write_info_before_PLTE,
@@ -1237,10 +1148,13 @@ PNG_EXPORT(22, void, png_read_info,
 #ifdef PNG_TIME_RFC1123_SUPPORTED
   /* Convert to a US string format: there is no localization support in this
    * routine.  The original implementation used a 29 character buffer in
-    * png_struct, this has been removed (in libpng 1.7.0).
+    * png_struct, this will be removed in future versions.
    */
-PNG_REMOVED(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
-    png_const_timep ptime),PNG_DEPRECATED)
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
+PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
+    png_const_timep ptime),PNG_DEPRECATED);
+#endif
 PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
    png_const_timep ptime));
 #endif
@@ -1662,8 +1576,22 @@ PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
 PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
    int filters));

+/* Flags for png_set_filter() to say which filters to use.  The flags
+ * are chosen so that they don't conflict with real filter types
+ * below, in case they are supplied instead of the #defined constants.
+ * These values should NOT be changed.
+ */
+#define PNG_NO_FILTERS     0x00
+#define PNG_FILTER_NONE    0x08
+#define PNG_FILTER_SUB     0x10
+#define PNG_FILTER_UP      0x20
+#define PNG_FILTER_AVG     0x40
+#define PNG_FILTER_PAETH   0x80
+#define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
+                         PNG_FILTER_AVG | PNG_FILTER_PAETH)
+
 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
- * These defines match the values in the PNG specification.
+ * These defines should NOT be changed.
 */
 #define PNG_FILTER_VALUE_NONE  0
 #define PNG_FILTER_VALUE_SUB   1
@@ -1672,26 +1600,6 @@ PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
 #define PNG_FILTER_VALUE_PAETH 4
 #define PNG_FILTER_VALUE_LAST  5

-/* The above values are valid arguments to png_set_filter() if only a single
- * filter is to be used.  If multiple filters are to be allowed (the default is
- * to allow any of them) then a combination of the following masks must be used
- * and the low three bits of the argument to png_set_filter must be 0.
- *
- * The resultant argument fits in a single byte.
- */
-#define PNG_FILTER_NONE    (0x08 << PNG_FILTER_VALUE_NONE)
-#define PNG_FILTER_SUB     (0x08 << PNG_FILTER_VALUE_SUB)
-#define PNG_FILTER_UP      (0x08 << PNG_FILTER_VALUE_UP)
-#define PNG_FILTER_AVG     (0x08 << PNG_FILTER_VALUE_AVG)
-#define PNG_FILTER_PAETH   (0x08 << PNG_FILTER_VALUE_PAETH)
-
-/* Then two convenience values.  PNG_NO_FILTERS is the same as
- * PNG_FILTER_VALUE_NONE, but this is harmless because they mean the same thing.
- */
-#define PNG_NO_FILTERS     0x00
-#define PNG_ALL_FILTERS    (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
-   PNG_FILTER_AVG | PNG_FILTER_PAETH)
-
 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
 /* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
 * defines, either the default (minimum-sum-of-absolute-differences), or
@@ -1896,14 +1804,12 @@ PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
 * The integer return from the callback function is interpreted thus:
 *
 * negative: An error occured, png_chunk_error will be called.
- *     zero: The chunk was not handled, the default unknown handling is used
- *           (even if this was a chunk that would otherwise be known.)
- *           NOTE: prior to libpng 1.7 handling values of
- *           PNG_HANDLE_CHUNK_AS_DEFAULT and PNG_HANDLE_CHUNK_NEVER were
- *           converted to PNG_HANDLE_CHUNK_IF_SAFE (libpng 1.6.0 warns if this
- *           happens) so it was not possible to discard unknown chunk data if a
- *           user callback was installed.
+ *     zero: The chunk was not handled, the chunk will be saved. A critical
+ *           chunk will cause an error at this point unless it is to be saved.
 * positive: The chunk was handled, libpng will ignore/discard it.
+ *
+ * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about
+ * how this behavior will change in libpng 1.7
 */
 PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
    png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
@@ -1927,7 +1833,7 @@ PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,

 /* Function to be called when data becomes available */
 PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
-    png_inforp info_ptr, png_bytep buffer, size_t buffer_size));
+    png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));

 /* A function which may be called *only* within png_process_data to stop the
 * processing of any more data.  The function returns the number of bytes
@@ -1936,7 +1842,7 @@ PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
 * 'save' is set to true the routine will first save all the pending data and
 * will always return 0.
 */
-PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save));
+PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));

 /* A function which may be called *only* outside (after) a call to
 * png_process_data.  It returns the number of bytes of data to skip in the
@@ -1979,13 +1885,16 @@ PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
 * in, it does not change the state for other png_info structures.
 *
 * 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. It was
- * removed in libpng 1.7.0.
+ * may result either in memory leaks or double free of allocated data.
 */
-PNG_REMOVED(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));

-/* Flags for png_free_data */
+/* Assignments for png_data_freer */
+#define PNG_DESTROY_WILL_FREE_DATA 1
+#define PNG_SET_WILL_FREE_DATA 1
+#define PNG_USER_WILL_FREE_DATA 2
+/* Flags for png_ptr->free_me and info_ptr->free_me */
 #define PNG_FREE_HIST 0x0008
 #define PNG_FREE_ICCP 0x0010
 #define PNG_FREE_SPLT 0x0020
@@ -2003,14 +1912,10 @@ PNG_REMOVED(99, void, png_data_freer, (png_const_structrp png_ptr,
 #define PNG_FREE_MUL  0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */

 #ifdef PNG_USER_MEM_SUPPORTED
-   /* These were deprecated in libpng 1.6.0 and have been removed from libpng
-    * 1.7.0; the functionality should be accessed by calling malloc or free
-    * directly or, if png_error handling is required, calling png_malloc.
-    */
-PNG_REMOVED(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
-    png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED)
-PNG_REMOVED(101, void, png_free_default, (png_const_structrp png_ptr,
-    png_voidp ptr), PNG_DEPRECATED)
+PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
+PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
+    png_voidp ptr), PNG_DEPRECATED);
 #endif

 #ifdef PNG_ERROR_TEXT_SUPPORTED
@@ -2083,7 +1988,7 @@ PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
    png_const_inforp info_ptr, png_uint_32 flag));

 /* Returns number of bytes needed to hold a transformed row. */
-PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr,
+PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
    png_const_inforp info_ptr));

 #ifdef PNG_INFO_IMAGE_SUPPORTED
@@ -2339,7 +2244,7 @@ PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
 #endif

 #ifdef PNG_sPLT_SUPPORTED
-PNG_EXPORT(161, void, png_set_sPLT, (png_structrp png_ptr,
+PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
 #endif

@@ -2357,7 +2262,7 @@ PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
 */

 #ifdef PNG_TEXT_SUPPORTED
-PNG_EXPORT(163, void, png_set_text, (png_structrp png_ptr,
+PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_textp text_ptr, int num_text));
 #endif

@@ -2384,14 +2289,15 @@ PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
 #endif

 #ifdef PNG_sCAL_SUPPORTED
-#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-/* NOTE: these API are currently implemented using floating point arithmetic,
- * consequently they can only be used on systems with floating point support.
+PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, int *unit, double *width, double *height))
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+   defined(PNG_FLOATING_POINT_SUPPORTED)
+/* NOTE: this API is currently implemented using floating point arithmetic,
+ * consequently it can only be used on systems with floating point support.
 * In any case the range of values supported by png_fixed_point is small and it
 * is highly recommended that png_get_sCAL_s be used instead.
 */
-PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
-    png_const_inforp info_ptr, int *unit, double *width, double *height))
 PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
    (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
    png_fixed_point *width, png_fixed_point *height))
@@ -2400,13 +2306,8 @@ PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
    (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
    png_charpp swidth, png_charpp sheight));

-#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-/* This also requires internal floating point arithmetic support - i.e. it
- * requires a full math library, not just floating point handling.
- */
 PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
    png_inforp info_ptr, int unit, double width, double height))
-#endif
 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
   png_inforp info_ptr, int unit, png_fixed_point width,
   png_fixed_point height))
@@ -2422,14 +2323,9 @@ PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
 * ignored and the default was used, the per-chunk setting only had an effect on
 * write.  If you wish to have chunk-specific handling on read in code that must
- * work on earlier versions you must use a user chunk callback to implement the
+ * work on earlier versions you must use a user chunk callback to specify the
 * desired handling (keep or discard.)
 *
- * NOTE: prior to 1.7.0 when a user callback returned '0', indicating that the
- * chunk had not been handled, libpng would preserve it regardless of the
- * default or per-chunk settings.  For compatibility with earlier versions
- * simply return '1' (handled) from the callback to discard the chunk.
- *
 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below.  The
 * parameter is interpreted as follows:
 *
@@ -2452,12 +2348,21 @@ PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
 * it simply resets the behavior to the libpng default.
 *
+ * INTERACTION WTIH USER CHUNK CALLBACKS:
 * The per-chunk handling is always used when there is a png_user_chunk_ptr
 * callback and the callback returns 0; the chunk is then always stored *unless*
 * it is critical and the per-chunk setting is other than ALWAYS.  Notice that
 * the global default is *not* used in this case.  (In effect the per-chunk
 * value is incremented to at least IF_SAFE.)
 *
+ * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
+ * per-chunk defaults will be honored.  If you want to preserve the current
+ * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
+ * as the default - if you don't do this libpng 1.6 will issue a warning.
+ *
+ * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
+ * earlier simply return '1' (handled).
+ *
 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
 *    If this is *not* set known chunks will always be handled by libpng and
 *    will never be stored in the unknown chunk list.  Known chunks listed to
@@ -2522,7 +2427,7 @@ PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
 #endif

 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
-PNG_EXPORT(174, void, png_set_unknown_chunks, (png_structrp png_ptr,
+PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_unknown_chunkp unknowns,
    int num_unknowns));
   /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
@@ -2796,18 +2701,27 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));

 #ifdef PNG_USE_READ_MACROS
 /* Inline macros to do direct reads of bytes from the input buffer.
+ * The png_get_int_32() routine assumes we are using two's complement
+ * format for negative values, which is almost certainly true.
 */
-#  define PNG_B(ptr, offset) (((png_const_bytep)(ptr))[offset])
 #  define PNG_get_uint_32(buf) \
-      PNG_U32(PNG_B(buf,0), PNG_B(buf,1), PNG_B(buf,2), PNG_B(buf,3))
+     (((png_uint_32)(*(buf)) << 24) + \
+      ((png_uint_32)(*((buf) + 1)) << 16) + \
+      ((png_uint_32)(*((buf) + 2)) << 8) + \
+      ((png_uint_32)(*((buf) + 3))))

   /* 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.
    */
-#  define PNG_get_uint_16(buf) PNG_U16(PNG_B(buf,0), PNG_B(buf,1))
+#  define PNG_get_uint_16(buf) \
+     ((png_uint_16) \
+      (((unsigned int)(*(buf)) << 8) + \
+       ((unsigned int)(*((buf) + 1)))))

 #  define PNG_get_int_32(buf) \
-      PNG_S32(PNG_B(buf,0), PNG_B(buf,1), PNG_B(buf,2), PNG_B(buf,3))
+     ((png_int_32)((*(buf) & 0x80) \
+      ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
+      : (png_int_32)png_get_uint_32(buf)))

   /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
    * but defining a macro name prefixed with PNG_PREFIX.
@@ -2826,63 +2740,8 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
 #  endif
 #endif

-#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
-PNG_EXPORT(242, void, png_set_check_for_invalid_index,
-    (png_structrp png_ptr, int allowed));
-#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
-PNG_EXPORT(243, int, png_get_palette_max, (png_const_structrp png_ptr,
-    png_const_inforp info_ptr));
-#  endif
-#endif /* CHECK_FOR_INVALID_INDEX */
-
 /*******************************************************************************
- *  IMPLEMENTATION OPTIONS
- *******************************************************************************
- *
- * Support for arbitrary implementation-specific optimizations.  The API allows
- * particular options to be turned on or off.  'Option' is the number of the
- * option and 'onoff' is 0 (off) or non-0 (on).  The value returned is given
- * by the PNG_OPTION_ defines below.
- *
- * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
- *           are detected at run time, however sometimes it may be impossible
- *           to do this in user mode, in which case it is necessary to discover
- *           the capabilities in an OS specific way.  Such capabilities are
- *           listed here when libpng has support for them and must be turned
- *           ON by the application if present.
- *
- * SOFTWARE: sometimes software optimizations actually result in performance
- *           decrease on some architectures or systems, or with some sets of
- *           PNG images.  'Software' options allow such optimizations to be
- *           selected at run time.
- */
-#ifdef PNG_SET_OPTION_SUPPORTED
-#ifdef PNG_ARM_NEON_API_SUPPORTED
-#  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 */
-
-/* Return values: NOTE: there are four values and 'off' is *not* zero */
-#define PNG_OPTION_UNSET   0 /* Unset - defaults to off */
-#define PNG_OPTION_INVALID 1 /* Option number out of range */
-#define PNG_OPTION_OFF     2
-#define PNG_OPTION_ON      3
-
-PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
-   int onoff));
-#endif
-
-/*******************************************************************************
- *  END OF HARDWARE OPTIONS
- ******************************************************************************/
-
-/* Maintainer: Put new public prototypes here ^, in libpng.3, and project
- * defs
- */
-
-/*******************************************************************************
- *  Section 5: SIMPLIFIED API
+ *  SIMPLIFIED API
 *******************************************************************************
 *
 * Please read the documentation in libpng-manual.txt (TODO: write said
@@ -3240,7 +3099,7 @@ PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
 #endif /* PNG_STDIO_SUPPORTED */

 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
-   png_const_voidp memory, size_t size));
+   png_const_voidp memory, png_size_t size));
   /* The PNG header is read from the given memory buffer. */

 PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
@@ -3334,6 +3193,61 @@ PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
 *  END OF SIMPLIFIED API
 ******************************************************************************/

+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+PNG_EXPORT(242, void, png_set_check_for_invalid_index,
+    (png_structrp png_ptr, int allowed));
+#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
+    png_const_infop info_ptr));
+#  endif
+#endif /* CHECK_FOR_INVALID_INDEX */
+
+/*******************************************************************************
+ *  IMPLEMENTATION OPTIONS
+ *******************************************************************************
+ *
+ * Support for arbitrary implementation-specific optimizations.  The API allows
+ * particular options to be turned on or off.  'Option' is the number of the
+ * option and 'onoff' is 0 (off) or non-0 (on).  The value returned is given
+ * by the PNG_OPTION_ defines below.
+ *
+ * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
+ *           are detected at run time, however sometimes it may be impossible
+ *           to do this in user mode, in which case it is necessary to discover
+ *           the capabilities in an OS specific way.  Such capabilities are
+ *           listed here when libpng has support for them and must be turned
+ *           ON by the application if present.
+ *
+ * SOFTWARE: sometimes software optimizations actually result in performance
+ *           decrease on some architectures or systems, or with some sets of
+ *           PNG images.  'Software' options allow such optimizations to be
+ *           selected at run time.
+ */
+#ifdef PNG_SET_OPTION_SUPPORTED
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+#  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 */
+
+/* Return values: NOTE: there are four values and 'off' is *not* zero */
+#define PNG_OPTION_UNSET   0 /* Unset - defaults to off */
+#define PNG_OPTION_INVALID 1 /* Option number out of range */
+#define PNG_OPTION_OFF     2
+#define PNG_OPTION_ON      3
+
+PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
+   int onoff));
+#endif
+
+/*******************************************************************************
+ *  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
+ */
+
 /* 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.
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@

 /* pngconf.h - machine configurable file for libpng
 *
- * libpng version 1.7.0beta34 - March 17, 2014
+ * libpng version 1.6.11beta02 - April 6, 2014
 *
 * Copyright (c) 1998-2013 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -238,6 +238,7 @@
 #      define PNGAPI _stdcall
 #    endif
 #  endif /* compiler/api */
+
  /* NOTE: PNGCBAPI always defaults to PNGCAPI. */

 #  if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
@@ -385,6 +386,7 @@
 #    ifndef PNG_RESTRICT
 #      define PNG_RESTRICT __restrict
 #    endif
+
 #  elif defined(__GNUC__)
 #    ifndef PNG_USE_RESULT
 #      define PNG_USE_RESULT __attribute__((__warn_unused_result__))
@@ -465,14 +467,6 @@
 #  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)\
-         PNG_EXPORT(ordinal, type, name, args);
-#  else                   /* No floating point APIs */
-#     define PNG_FP_EXPORT(ordinal, type, name, args)
-#  endif
-#endif
 #ifndef PNG_FP_EXPORT     /* A floating point API. */
 #  ifdef PNG_FLOATING_POINT_SUPPORTED
 #     define PNG_FP_EXPORT(ordinal, type, name, args)\
@@ -545,8 +539,6 @@

 /* Prior to 1.6.0 it was possible to disable the use of size_t, 1.6.0, however,
 * requires an ISOC90 compiler and relies on consistent behavior of sizeof.
- *
- * DEPRECATED: don't use these types, instead use size_t and ptrdiff_t.
 */
 typedef size_t png_size_t;
 typedef ptrdiff_t png_ptrdiff_t;
@@ -567,13 +559,13 @@ typedef ptrdiff_t png_ptrdiff_t;
 #  endif
 #endif

-/* png_alloc_size_t is guaranteed to be no smaller than size_t, and no
- * smaller than png_uint_32.  Casts from size_t or png_uint_32 to
+/* png_alloc_size_t is guaranteed to be no smaller than png_size_t, and no
+ * smaller than png_uint_32.  Casts from png_size_t or png_uint_32 to
 * png_alloc_size_t are not necessary; in fact, it is recommended not to use
 * them at all so that the compiler can complain when something turns out to be
 * problematic.
 *
- * Casts in the other direction (from png_alloc_size_t to size_t or
+ * Casts in the other direction (from png_alloc_size_t to png_size_t or
 * png_uint_32) should be explicitly applied; however, we do not expect to
 * encounter practical situations that require such conversions.
 *
@@ -583,7 +575,7 @@ typedef ptrdiff_t png_ptrdiff_t;
 #ifdef PNG_SMALL_SIZE_T
   typedef png_uint_32 png_alloc_size_t;
 #else
-   typedef size_t png_alloc_size_t;
+   typedef png_size_t png_alloc_size_t;
 #endif

 /* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler
@@ -619,8 +611,8 @@ typedef char                  * png_charp;
 typedef const char            * png_const_charp;
 typedef png_fixed_point       * png_fixed_point_p;
 typedef const png_fixed_point * png_const_fixed_point_p;
-typedef size_t                * png_size_tp;
-typedef const size_t          * png_const_size_tp;
+typedef png_size_t            * png_size_tp;
+typedef const png_size_t      * png_const_size_tp;

 #ifdef PNG_STDIO_SUPPORTED
 typedef FILE            * png_FILE_p;
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,7 +1,7 @@

 /* pngerror.c - stub functions for i/o and memory allocation
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.11 [(PENDING RELEASE)]
 * 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.)
@@ -567,13 +567,7 @@ png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
 }

 #ifdef PNG_ERROR_TEXT_SUPPORTED
-
-#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
-   (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
-   defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
-   (defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) &&\
-   defined(PNG_sCAL_SUPPORTED))
+#ifdef PNG_FLOATING_POINT_SUPPORTED
 PNG_FUNCTION(void,
 png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
 {
@@ -765,19 +759,18 @@ 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)
      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
    * choice is to terminate the whole process (or maybe the thread); to do
    * this the ANSI-C abort() function is used unless a different method is 
    * implemented by overriding the default configuration setting for
-    * PNG_ABORT (see scripts/pnglibconf.dfa).
-    *
-    * API change: prior to 1.7.0 PNG_ABORT was invoked as a function type macro
-    * with no arguments 'PNG_ABORT();', in 1.7.0 this is changed to a simple
-    * macro that is defined in the configuration.
+    * PNG_ABORT().
    */
-   PNG_ABORT
+   PNG_ABORT();
 }

 #ifdef PNG_WARNINGS_SUPPORTED
--- a/pngget.c
+++ b/pngget.c
@@ -1,7 +1,7 @@

 /* pngget.c - retrieval of values from info struct
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.11 [(PENDING RELEASE)]
 * 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.)
@@ -124,6 +124,9 @@ 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);
@@ -142,6 +145,9 @@ 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);
@@ -159,6 +165,9 @@ 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);
@@ -229,6 +238,9 @@ png_get_x_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
      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);
@@ -245,6 +257,9 @@ png_get_y_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
      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);
@@ -261,6 +276,9 @@ png_get_x_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
      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);
@@ -277,6 +295,9 @@ png_get_y_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
      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);
@@ -843,8 +864,9 @@ png_get_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
 #endif

 #ifdef PNG_sCAL_SUPPORTED
-#  ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-#     ifdef PNG_FIXED_POINT_SUPPORTED
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+#    if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+         defined(PNG_FLOATING_POINT_SUPPORTED)
 png_uint_32 PNGAPI
 png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, png_fixed_point *width, png_fixed_point *height)
@@ -865,9 +887,9 @@ png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,

   return(0);
 }
-#     endif /* FIXED_POINT */
-
-#     ifdef PNG_FLOATING_POINT_SUPPORTED
+#    endif /* FLOATING_ARITHMETIC */
+#  endif /* FIXED_POINT */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
 png_uint_32 PNGAPI
 png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, double *width, double *height)
@@ -883,9 +905,7 @@ png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr,

   return(0);
 }
-#     endif /* FLOATING POINT */
-#  endif /* FLOATING_ARITHMETIC */
-
+#  endif /* FLOATING POINT */
 png_uint_32 PNGAPI
 png_get_sCAL_s(png_const_structrp png_ptr, png_const_inforp info_ptr,
    int *unit, png_charpp width, png_charpp height)
@@ -1165,7 +1185,7 @@ png_get_io_chunk_type (png_const_structrp png_ptr)
 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
 #  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
 int PNGAPI
-png_get_palette_max(png_const_structrp png_ptr, png_const_inforp info_ptr)
+png_get_palette_max(png_const_structp png_ptr, png_const_infop info_ptr)
 {
   if (png_ptr != NULL && info_ptr != NULL)
      return png_ptr->num_palette_max;
--- a/pngmem.c
+++ b/pngmem.c
@@ -1,8 +1,8 @@

 /* pngmem.c - stub functions for memory allocation
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.8 [December 19, 2013]
+ * Copyright (c) 1998-2013 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.)
 *
@@ -126,7 +126,7 @@ png_malloc_array,(png_const_structrp png_ptr, int nelements,
 }

 PNG_FUNCTION(png_voidp /* PRIVATE */,
-png_realloc_array,(png_structrp png_ptr, png_const_voidp old_array,
+png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array,
   int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED)
 {
   /* These are internal errors: */
@@ -157,15 +157,6 @@ png_realloc_array,(png_structrp png_ptr, png_const_voidp old_array,
      }
   }

-#ifdef PNG_READ_SUPPORTED
-# ifdef PNG_USER_LIMITS_SUPPORTED
-   /* The potential overflow case.  Set the cache counter so libpng will
-    * not make any more attempts
-    */
-   png_ptr->user_chunk_cache_max = 2;
-# endif
-#endif
-
   return NULL; /* error */
 }
 #endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */
@@ -185,11 +176,31 @@ png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
   ret = png_malloc_base(png_ptr, size);

   if (ret == NULL)
-       png_error(png_ptr, "Out of memory");
+       png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */

   return ret;
 }

+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),
+   PNG_ALLOCATED PNG_DEPRECATED)
+{
+   png_voidp ret;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   /* Passing 'NULL' here bypasses the application provided memory handler. */
+   ret = png_malloc_base(NULL/*use malloc*/, size);
+
+   if (ret == NULL)
+      png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */
+
+   return ret;
+}
+#endif /* PNG_USER_MEM_SUPPORTED */
+
 /* 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
 * png_error, if it fails to allocate the requested memory.
@@ -225,8 +236,17 @@ png_free(png_const_structrp png_ptr, png_voidp ptr)
      png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr);

   else
+      png_free_default(png_ptr, ptr);
+}
+
+PNG_FUNCTION(void,PNGAPI
+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 */
-      free(ptr);
+
+   free(ptr);
 }

 #ifdef PNG_USER_MEM_SUPPORTED
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,7 +1,7 @@

 /* pngpread.c - read a png file in push mode
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.11 [(PENDING RELEASE)]
 * 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.)
@@ -185,7 +185,7 @@ void /* PRIVATE */
 png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
 {
   png_uint_32 chunk_name;
-#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   int keep; /* unknown handling method */
 #endif

@@ -241,7 +241,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
            return;

      if (png_ptr->mode & PNG_AFTER_IDAT)
-         png_benign_error(png_ptr, "Too many IDATs found[p]");
+         png_benign_error(png_ptr, "Too many IDATs found");
   }

   if (chunk_name == png_IHDR)
@@ -272,7 +272,7 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
      png_push_have_end(png_ptr, info_ptr);
   }

-#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+#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)
@@ -979,15 +979,15 @@ png_push_process_row(png_structrp png_ptr)


 #ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Blow up interlaced rows to full size */
+   /* Expand interlaced rows to full size */
   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
   {
      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;
--- 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 1.7.0 [(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
@@ -40,17 +40,10 @@
 #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */

 #ifndef PNG_VERSION_INFO_ONLY
-/* Keep standard libraries at the top of this file */
-
 /* Standard library headers not required by png.h: */
 #  include <stdlib.h>
 #  include <string.h>
-
-/* For headers only required with some build configurations see the lines after
- * pnglibconf.h is included!
- */
-
-#endif /* VERSION_INFO_ONLY */
+#endif

 #define PNGLIB_BUILD /*libpng is being built, not used*/

@@ -95,36 +88,6 @@
 #  endif
 #endif

-#ifndef PNG_VERSION_INFO_ONLY
-/* Additional standard libaries required in certain cases, put only standard
- * ANSI-C89 headers here.  If not available, or non-functional, the problem
- * should be fixed by writing a wrapper for the header and the file on your
- * include path.
- */
-#if defined(PNG_sCAL_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
-   /* png.c requires the following ANSI-C constants if the conversion of
-    * floating point to ASCII is implemented therein:
-    *
-    *  DBL_MIN_10_EXP Minimum negative integer such that 10^integer is a
-    *                 normalized (double) value.
-    *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
-    *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
-    *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
-    */
-#  include <float.h>
-#endif /* sCAL && FLOATING_POINT */
-
-#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) ||\
-   defined(PNG_FLOATING_POINT_SUPPORTED)
-   /* ANSI-C90 math functions are required.  Full compliance with the standard
-    * is probably not a requirement, but the functions must exist and be
-    * declared in <math.h>
-    */
-#  include <math.h>
-#endif /* FLOATING_ARITHMETIC || FLOATING_POINT */
-
-#endif /* VERSION_INFO_ONLY */
-
 /* Compile time options.
 * =====================
 * In a multi-arch build the compiler may compile the code several times for the
@@ -324,9 +287,6 @@
 #  endif
 #endif

-/* Include png.h here to get the version info and other macros, pngstruct.h and
- * pnginfo.h are included later under the protection of !PNG_VERSION_INFO_ONLY
- */
 #include "png.h"

 /* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
@@ -334,17 +294,6 @@
 #  define PNG_DLL_EXPORT
 #endif

-/* asserts are turned off in release code, but are in even in release candidates
- * because often system builders only check future libpng releases when a
- * release candidate is available.
- */
-#if PNG_LIBPNG_BUILD_BASE_TYPE == PNG_LIBPNG_BUILD_STABLE
-#  define NDEBUG
-#endif
-#ifndef PNG_VERSION_INFO_ONLY
-#  include <assert.h>
-#endif
-
 /* SECURITY and SAFETY:
 *
 * By default libpng is built without any internal limits on image size,
@@ -468,6 +417,67 @@
 #  define PNGFAPI /* PRIVATE */
 #endif

+#ifndef PNG_VERSION_INFO_ONLY
+/* Other defines specific to compilers can go here.  Try to keep
+ * them inside an appropriate ifdef/endif pair for portability.
+ */
+#if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
+    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+   /* png.c requires the following ANSI-C constants if the conversion of
+    * floating point to ASCII is implemented therein:
+    *
+    *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
+    *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
+    *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
+    */
+#  include <float.h>
+
+#  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
+    defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
+     /* We need to check that <math.h> hasn't already been included earlier
+      * as it seems it doesn't agree with <fp.h>, yet we should really use
+      * <fp.h> if possible.
+      */
+#    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
+#      include <fp.h>
+#    endif
+#  else
+#    include <math.h>
+#  endif
+#  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
+     /* Amiga SAS/C: We must include builtin FPU functions when compiling using
+      * MATH=68881
+      */
+#    include <m68881.h>
+#  endif
+#endif
+
+/* This provides the non-ANSI (far) memory allocation routines. */
+#if defined(__TURBOC__) && defined(__MSDOS__)
+#  include <mem.h>
+#  include <alloc.h>
+#endif
+
+#if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
+    defined(_WIN32) || defined(__WIN32__)
+#  include <windows.h>  /* defines _WINDOWS_ macro */
+#endif
+#endif /* PNG_VERSION_INFO_ONLY */
+
+/* Moved here around 1.5.0beta36 from pngconf.h */
+/* Users may want to use these so they are not private.  Any library
+ * functions that are passed far data must be model-independent.
+ */
+
+/* Memory model/platform independent fns */
+#ifndef PNG_ABORT
+#  ifdef _WINDOWS_
+#    define PNG_ABORT() ExitProcess(0)
+#  else
+#    define PNG_ABORT() abort()
+#  endif
+#endif
+
 /* These macros may need to be architecture dependent. */
 #define PNG_ALIGN_NONE   0 /* do not use data alignment */
 #define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
@@ -536,7 +546,7 @@
 #define PNG_HAVE_CHUNK_HEADER      0x100
 #define PNG_WROTE_tIME             0x200
 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
-                   /*              0x800 (unused) */
+#define PNG_BACKGROUND_IS_GRAY     0x800
 #define PNG_HAVE_PNG_SIGNATURE    0x1000
 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
                   /*             0x4000 (unused) */
@@ -550,10 +560,10 @@
 #define PNG_SWAP_BYTES          0x0010
 #define PNG_INVERT_MONO         0x0020
 #define PNG_QUANTIZE            0x0040
-#define PNG_COMPOSE             0x0080 /* Was PNG_BACKGROUND */
-                       /*       0x0100 unused */
-#define PNG_EXPAND_16           0x0200 /* Added to libpng 1.5.2 */
-#define PNG_16_TO_8             0x0400 /* Becomes 'chop' in 1.5.4 */
+#define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
+#define PNG_BACKGROUND_EXPAND   0x0100
+#define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
+#define PNG_16_TO_8             0x0400     /* Becomes 'chop' in 1.5.4 */
 #define PNG_RGBA                0x0800
 #define PNG_EXPAND              0x1000
 #define PNG_GAMMA               0x2000
@@ -568,13 +578,13 @@
 #define PNG_RGB_TO_GRAY_WARN  0x400000
 #define PNG_RGB_TO_GRAY       0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
 #define PNG_ENCODE_ALPHA      0x800000 /* Added to libpng-1.5.4 */
-#define PNG_ADD_ALPHA        0x1000000 /* Added to libpng-1.2.7 */
-#define PNG_EXPAND_tRNS      0x2000000 /* Added to libpng-1.2.9 */
-#define PNG_SCALE_16_TO_8    0x4000000 /* Added to libpng-1.5.4 */
-                       /*    0x8000000 unused */
-                       /*   0x10000000 unused */
-                       /*   0x20000000 unused */
-                       /*   0x40000000 unused */
+#define PNG_ADD_ALPHA         0x1000000 /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS       0x2000000 /* Added to libpng-1.2.9 */
+#define PNG_SCALE_16_TO_8     0x4000000 /* Added to libpng-1.5.4 */
+                       /*   0x8000000 unused */
+                       /*  0x10000000 unused */
+                       /*  0x20000000 unused */
+                       /*  0x40000000 unused */
 /* Flags for png_create_struct */
 #define PNG_STRUCT_PNG   0x0001
 #define PNG_STRUCT_INFO  0x0002
@@ -607,8 +617,8 @@
 #define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000 /* Added to libpng-1.4.0 */
 #define PNG_FLAG_APP_WARNINGS_WARN      0x200000 /* Added to libpng-1.6.0 */
 #define PNG_FLAG_APP_ERRORS_WARN        0x400000 /* Added to libpng-1.6.0 */
-#define PNG_FLAG_BACKGROUND_IS_GRAY     0x800000
-#define PNG_FLAG_BACKGROUND_EXPAND     0x1000000
+                                  /*    0x800000    unused */
+                                  /*   0x1000000    unused */
                                  /*   0x2000000    unused */
                                  /*   0x4000000    unused */
                                  /*   0x8000000    unused */
@@ -631,16 +641,6 @@
   abs((int)((c1).green) - (int)((c2).green)) + \
   abs((int)((c1).blue) - (int)((c2).blue)))

-#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
-   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
-/* See below for the definitions of the tables used in these macros */
-#define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
-   ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
-   /* 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 */
-
 /* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
 * by dividing by 257 *with rounding*.  This macro is exact for the given range.
 * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
@@ -705,6 +705,98 @@
 */
 #endif

+/* Constants for known chunk types.  If you need to add a chunk, define the name
+ * here.  For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case.  Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.
+ *
+ * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
+ * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
+ * to be generated if required.
+ *
+ * PNG_32b correctly produces a value shifted by up to 24 bits, even on
+ * architectures where (int) is only 16 bits.
+ */
+#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
+#define PNG_U32(b1,b2,b3,b4) \
+   (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
+
+/* Constants for known chunk types.
+ *
+ * MAINTAINERS: If you need to add a chunk, define the name here.
+ * For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case.  Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.  Please keep the list sorted.
+ *
+ * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
+ * type.  In fact the specification does not express chunk types this way,
+ * however using a 32-bit value means that the chunk type can be read from the
+ * stream using exactly the same code as used for a 32-bit unsigned value and
+ * can be examined far more efficiently (using one arithmetic compare).
+ *
+ * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
+ * libpng API still uses strings for 'unknown' chunks and a macro,
+ * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
+ * that for portable code numeric values must still be used; the string "IHDR"
+ * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
+ *
+ * In 1.7.0 the definitions will be made public in png.h to avoid having to
+ * duplicate the same definitions in application code.
+ */
+#define png_IDAT PNG_U32( 73,  68,  65,  84)
+#define png_IEND PNG_U32( 73,  69,  78,  68)
+#define png_IHDR PNG_U32( 73,  72,  68,  82)
+#define png_PLTE PNG_U32( 80,  76,  84,  69)
+#define png_bKGD PNG_U32( 98,  75,  71,  68)
+#define png_cHRM PNG_U32( 99,  72,  82,  77)
+#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
+#define png_gAMA PNG_U32(103,  65,  77,  65)
+#define png_gIFg PNG_U32(103,  73,  70, 103)
+#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
+#define png_gIFx PNG_U32(103,  73,  70, 120)
+#define png_hIST PNG_U32(104,  73,  83,  84)
+#define png_iCCP PNG_U32(105,  67,  67,  80)
+#define png_iTXt PNG_U32(105,  84,  88, 116)
+#define png_oFFs PNG_U32(111,  70,  70, 115)
+#define png_pCAL PNG_U32(112,  67,  65,  76)
+#define png_pHYs PNG_U32(112,  72,  89, 115)
+#define png_sBIT PNG_U32(115,  66,  73,  84)
+#define png_sCAL PNG_U32(115,  67,  65,  76)
+#define png_sPLT PNG_U32(115,  80,  76,  84)
+#define png_sRGB PNG_U32(115,  82,  71,  66)
+#define png_sTER PNG_U32(115,  84,  69,  82)
+#define png_tEXt PNG_U32(116,  69,  88, 116)
+#define png_tIME PNG_U32(116,  73,  77,  69)
+#define png_tRNS PNG_U32(116,  82,  78,  83)
+#define png_zTXt PNG_U32(122,  84,  88, 116)
+
+/* The following will work on (signed char*) strings, whereas the get_uint_32
+ * macro will fail on top-bit-set values because of the sign extension.
+ */
+#define PNG_CHUNK_FROM_STRING(s)\
+   PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
+
+/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
+ * signed and the argument is a (char[])  This macro will fail miserably on
+ * systems where (char) is more than 8 bits.
+ */
+#define PNG_STRING_FROM_CHUNK(s,c)\
+   (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
+   ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
+
+/* Do the same but terminate with a null character. */
+#define PNG_CSTRING_FROM_CHUNK(s,c)\
+   (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
+
+/* Test on flag values as defined in the spec (section 5.4): */
+#define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
+#define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
+#define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
+#define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
+#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
+
 /* Gamma values (new at libpng-1.5.4): */
 #define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
 #define PNG_GAMMA_MAC_INVERSE 65909
@@ -753,6 +845,12 @@ PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);

 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
+
+#define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
+   ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
+   /* 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 */


@@ -781,16 +879,6 @@ PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
   /* Free the buffer list used by the compressed write code. */
 #endif

-#ifdef PNG_WRITE_FILTER_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_write_alloc_filter_row_buffers,
-   (png_structrp png_ptr, int filters),PNG_EMPTY);
-   /* Allocate pixel row buffers to cache filtered rows while testing candidate
-    * filters.
-    * TODO: avoid this, only one spare row buffer (at most) is required, this
-    * wastes a lot of memory for large images.
-    */
-#endif
-
 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
   !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
   (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
@@ -818,7 +906,7 @@ PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
   defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
 /* Internal array allocator, outputs no error or warning messages on failure,
- * just returns NULL.
+ * just returns NULL.  
 */
 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
   int nelements, size_t element_size),PNG_ALLOCATED);
@@ -827,7 +915,7 @@ PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
 * also memsets the new elements to 0 and copies the old elements.  The old
 * array is not freed or altered.
 */
-PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_structrp png_ptr,
+PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
   png_const_voidp array, int old_elements, int add_elements,
   size_t element_size),PNG_ALLOCATED);
 #endif /* text, sPLT or unknown chunks */
@@ -1008,7 +1096,7 @@ PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
 #endif

 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
-PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_structrp png_ptr,
+PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
 #endif

@@ -1762,7 +1850,7 @@ PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
   png_fixed_point gamma_value),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
   PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_build_gamma_tables,(png_structrp png_ptr,
+PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
   int bit_depth),PNG_EMPTY);
 #endif

@@ -1828,7 +1916,7 @@ PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
 * the generic code is used.
 */
 #ifdef PNG_FILTER_OPTIMIZATIONS
-PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structrp png_ptr,
+PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
   unsigned int bpp), PNG_EMPTY);
   /* Just declare the optimization that will be used */
 #else
--- a/pngread.c
+++ b/pngread.c
@@ -1,7 +1,7 @@

 /* pngread.c - read a PNG file
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.11 [(PENDING RELEASE)]
 * 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.)
@@ -121,7 +121,7 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
            png_chunk_error(png_ptr, "Missing PLTE before IDAT");

         else if (png_ptr->mode & PNG_AFTER_IDAT)
-            png_chunk_benign_error(png_ptr, "Too many IDATs found[s]");
+            png_chunk_benign_error(png_ptr, "Too many IDATs found");

         png_ptr->mode |= PNG_HAVE_IDAT;
      }
@@ -572,7 +572,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
      png_error(png_ptr, "internal sequential row size calculation error");

 #ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* Blow up interlaced rows to full size */
+   /* Expand interlaced rows to full size */
   if (png_ptr->interlaced &&
      (png_ptr->transformations & PNG_INTERLACE))
   {
@@ -796,7 +796,7 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
         if (chunk_name == png_IDAT)
         {
            if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
-               png_benign_error(png_ptr, "Too many IDATs found(a1)");
+               png_benign_error(png_ptr, "Too many IDATs found");
         }
         png_handle_unknown(png_ptr, info_ptr, length, keep);
         if (chunk_name == png_PLTE)
@@ -810,7 +810,7 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
          * read, but not after other chunks have been read.
          */
         if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
-            png_benign_error(png_ptr, "Too many IDATs found(a2)");
+            png_benign_error(png_ptr, "Too many IDATs found");

         png_crc_finish(png_ptr, length);
      }
@@ -945,7 +945,7 @@ png_read_destroy(png_structrp png_ptr)
   png_free(png_ptr, png_ptr->save_buffer);
 #endif

-#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) && \
+#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) &&\
   defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
   png_free(png_ptr, png_ptr->unknown_chunk.data);
 #endif
@@ -3317,11 +3317,11 @@ png_image_read_composite(png_voidp argument)
 * PNG_COMPOSITE
 * PNG_GAMMA
 *
- * This is a work-round for the fact that both the PNG_RGB_TO_GRAY and
+ * This is a work-around for the fact that both the PNG_RGB_TO_GRAY and
 * PNG_COMPOSITE code performs gamma correction, so we get double gamma
- * correction.  The fix-up is to prevent the PNG_COMPOSITE operation happening
- * inside libpng, so this routine sees an 8 or 16-bit gray+alpha row and handles
- * the removal or pre-multiplication of the alpha channel.
+ * correction.  The fix-up is to prevent the PNG_COMPOSITE operation from
+ * happening inside libpng, so this routine sees an 8 or 16-bit gray+alpha
+ * row and handles the removal or pre-multiplication of the alpha channel.
 */
 static int
 png_image_read_background(png_voidp argument)
--- a/pngrtran.c
+++ b/pngrtran.c
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,7 +1,7 @@

 /* pngrutil.c - utilities to read a PNG file
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.11 [(PENDING RELEASE)]
 * 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.)
@@ -18,6 +18,17 @@

 #ifdef PNG_READ_SUPPORTED

+png_uint_32 PNGAPI
+png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
+{
+   png_uint_32 uval = png_get_uint_32(buf);
+
+   if (uval > PNG_UINT_31_MAX)
+      png_error(png_ptr, "PNG unsigned integer out of range");
+
+   return (uval);
+}
+
 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
 /* The following is a variation on the above for use with the fixed
 * point values used for gAMA and cHRM.  Instead of png_error it
@@ -40,7 +51,7 @@ png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)

   return PNG_FIXED_ERROR;
 }
-#endif /* READ_gAMA or READ_cHRM */
+#endif

 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
 /* NOTE: the read macros will obscure these definitions, so that if
@@ -56,7 +67,13 @@ png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
 png_uint_32 (PNGAPI
 png_get_uint_32)(png_const_bytep buf)
 {
-   return PNG_U32(buf[0], buf[1], buf[2], buf[3]);
+   png_uint_32 uval =
+       ((png_uint_32)(*(buf    )) << 24) +
+       ((png_uint_32)(*(buf + 1)) << 16) +
+       ((png_uint_32)(*(buf + 2)) <<  8) +
+       ((png_uint_32)(*(buf + 3))      ) ;
+
+   return uval;
 }

 /* Grab a signed 32-bit integer from a buffer in big-endian format.  The
@@ -67,32 +84,32 @@ png_get_uint_32)(png_const_bytep buf)
 png_int_32 (PNGAPI
 png_get_int_32)(png_const_bytep buf)
 {
-   return PNG_S32(buf[0], buf[1], buf[2], buf[3]);
+   png_uint_32 uval = png_get_uint_32(buf);
+   if ((uval & 0x80000000) == 0) /* non-negative */
+      return uval;
+
+   uval = (uval ^ 0xffffffff) + 1;  /* 2's complement: -x = ~x+1 */
+   return -(png_int_32)uval;
 }

 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
 png_uint_16 (PNGAPI
 png_get_uint_16)(png_const_bytep buf)
 {
-   return PNG_U16(buf[0], buf[1]);
+   /* ANSI-C requires an int value to accomodate at least 16 bits so this
+    * works and allows the compiler not to worry about possible narrowing
+    * on 32 bit systems.  (Pre-ANSI systems did not make integers smaller
+    * than 16 bits either.)
+    */
+   unsigned int val =
+       ((unsigned int)(*buf) << 8) +
+       ((unsigned int)(*(buf + 1)));
+
+   return (png_uint_16)val;
 }
+
 #endif /* PNG_READ_INT_FUNCTIONS_SUPPORTED */

-/* This is an exported function however its error handling is too harsh for most
- * internal use.  For example if it were used for reading the chunk parameters
- * it would error out even on ancillary chunks that can be ignored.
- */
-png_uint_32 PNGAPI
-png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
-{
-   png_uint_32 uval = png_get_uint_32(buf);
-
-   if (uval > PNG_UINT_31_MAX)
-      png_error(png_ptr, "PNG unsigned integer out of range");
-
-   return uval;
-}
-
 /* Read and check the PNG file signature */
 void /* PRIVATE */
 png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
@@ -559,7 +576,7 @@ png_decompress_chunk(png_structrp png_ptr,
    */
   png_alloc_size_t limit = PNG_SIZE_MAX;

-#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+#  ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
      if (png_ptr->user_chunk_malloc_max > 0 &&
         png_ptr->user_chunk_malloc_max < limit)
         limit = png_ptr->user_chunk_malloc_max;
@@ -969,9 +986,7 @@ png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

      /* Otherwise, we (optionally) emit a warning and use the chunk. */
      else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN))
-      {
         png_chunk_warning(png_ptr, "CRC error");
-      }
   }
 #endif

@@ -1580,8 +1595,7 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

      if (--png_ptr->user_chunk_cache_max == 1)
      {
-         /* Warn the first time */
-         png_chunk_benign_error(png_ptr, "chunk cache full");
+         png_warning(png_ptr, "No space in chunk cache for sPLT");
         png_crc_finish(png_ptr, length);
         return;
      }
@@ -1658,8 +1672,8 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

   if (dl > max_dl)
   {
-      png_warning(png_ptr, "sPLT chunk too long");
-      return;
+       png_warning(png_ptr, "sPLT chunk too long");
+       return;
   }

   new_palette.nentries = (png_int_32)(data_length / entry_size);
@@ -1669,8 +1683,8 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)

   if (new_palette.entries == NULL)
   {
-      png_warning(png_ptr, "sPLT chunk requires too much memory");
-      return;
+       png_warning(png_ptr, "sPLT chunk requires too much memory");
+       return;
   }

 #ifdef PNG_POINTER_INDEXING_SUPPORTED
@@ -1831,8 +1845,6 @@ png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    */
   png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
       &(png_ptr->trans_color));
-
-   png_ptr->trans_alpha = info_ptr->trans_alpha;
 }
 #endif

@@ -2371,7 +2383,7 @@ png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
      if (--png_ptr->user_chunk_cache_max == 1)
      {
         png_crc_finish(png_ptr, length);
-         png_chunk_benign_error(png_ptr, "chunk cache full");
+         png_chunk_benign_error(png_ptr, "no space in chunk cache");
         return;
      }
   }
@@ -2450,7 +2462,7 @@ png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
      if (--png_ptr->user_chunk_cache_max == 1)
      {
         png_crc_finish(png_ptr, length);
-         png_chunk_benign_error(png_ptr, "chunk cache full");
+         png_chunk_benign_error(png_ptr, "no space in chunk cache");
         return;
      }
   }
@@ -2559,7 +2571,7 @@ png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
      if (--png_ptr->user_chunk_cache_max == 1)
      {
         png_crc_finish(png_ptr, length);
-         png_chunk_benign_error(png_ptr, "chunk cache full");
+         png_chunk_benign_error(png_ptr, "no space in chunk cache");
         return;
      }
   }
@@ -2699,7 +2711,7 @@ png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
      png_ptr->unknown_chunk.data = NULL;
   }

-#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+#  ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
      if (png_ptr->user_chunk_malloc_max > 0 &&
         png_ptr->user_chunk_malloc_max < limit)
         limit = png_ptr->user_chunk_malloc_max;
@@ -2803,16 +2815,31 @@ png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,

            else if (ret == 0)
            {
-               /* Use the default handling, note that if there is per-chunk
-                * handling specified it has already been set into 'keep'.
+               /* If the keep value is 'default' or 'never' override it, but
+                * still error out on critical chunks unless the keep value is
+                * 'always'  While this is weird it is the behavior in 1.4.12.
+                * A possible improvement would be to obey the value set for the
+                * chunk, but this would be an API change that would probably
+                * damage some applications.
                *
-                * NOTE: this is an API change in 1.7.0. Prior to 1.7.0 libpng
-                * would force keep to PNG_HANDLE_CHUNK_IF_SAFE at this point,
-                * and 1.6.0 would issue a warning if this caused a default of
-                * discarding the chunk to be changed.
+                * The png_app_warning below catches the case that matters, where
+                * the application has not set specific save or ignore for this
+                * chunk or global save or ignore.
                */
-               if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
-                  keep = png_ptr->unknown_default;
+               if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
+               {
+#                 ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+                     if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
+                     {
+                        png_chunk_warning(png_ptr, "Saving unknown chunk:");
+                        png_app_warning(png_ptr,
+                           "forcing save of an unhandled chunk;"
+                           " please call png_set_keep_unknown_chunks");
+                           /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
+                     }
+#                 endif
+                  keep = PNG_HANDLE_CHUNK_IF_SAFE;
+               }
            }

            else /* chunk was handled */
@@ -2884,7 +2911,7 @@ png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
         {
            case 2:
               png_ptr->user_chunk_cache_max = 1;
-               png_chunk_benign_error(png_ptr, "chunk cache full");
+               png_chunk_benign_error(png_ptr, "no space in chunk cache");
               /* FALL THROUGH */
            case 1:
               /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
@@ -3126,7 +3153,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
 #        define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
            S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }

-#        define B_MASKS(d,s) { B_MASK(1,d,s), S_MASK(3,d,s), S_MASK(5,d,s) }
+#        define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }

 #        define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))

@@ -3165,7 +3192,7 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
 #endif /* !PNG_USE_COMPILE_TIME_MASKS */

         /* Use the appropriate mask to copy the required bits.  In some cases
-          * the byte mask will be 0 or 0xff, optimize these cases.  row_width is
+          * the byte mask will be 0 or 0xff; optimize these cases.  row_width is
          * the number of pixels, but the code copies bytes, so it is necessary
          * to special case the end.
          */
@@ -4366,7 +4393,7 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
      png_error(png_ptr, "This image requires a row greater than 64KB");
 #endif

-   if (row_bytes + 48 > png_ptr->big_row_buf_size)
+   if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
   {
     png_free(png_ptr, png_ptr->big_row_buf);
     png_free(png_ptr, png_ptr->big_prev_row);
@@ -4403,7 +4430,7 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
     png_ptr->row_buf = png_ptr->big_row_buf + 31;
     png_ptr->prev_row = png_ptr->big_prev_row + 31;
 #endif
-     png_ptr->big_row_buf_size = row_bytes + 48;
+     png_ptr->old_big_row_buf_size = row_bytes + 48;
   }

 #ifdef PNG_MAX_MALLOC_64K
--- a/pngset.c
+++ b/pngset.c
@@ -1,7 +1,7 @@

 /* pngset.c - storage of image information into info struct
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.11 [(PENDING RELEASE)]
 * 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.)
@@ -422,8 +422,7 @@ png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
   info_ptr->free_me |= PNG_FREE_SCAL;
 }

-#  if defined(PNG_FLOATING_POINT_SUPPORTED) &&\
-      defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
 void PNGAPI
 png_set_sCAL(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
    double width, double height)
@@ -681,7 +680,7 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,

 #ifdef PNG_TEXT_SUPPORTED
 void PNGAPI
-png_set_text(png_structrp png_ptr, png_inforp info_ptr,
+png_set_text(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_textp text_ptr, int num_text)
 {
   int ret;
@@ -692,7 +691,7 @@ png_set_text(png_structrp png_ptr, png_inforp info_ptr,
 }

 int /* PRIVATE */
-png_set_text_2(png_structrp png_ptr, png_inforp info_ptr,
+png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
    png_const_textp text_ptr, int num_text)
 {
   int i;
@@ -739,7 +738,6 @@ png_set_text_2(png_structrp png_ptr, png_inforp info_ptr,
      {
         png_chunk_report(png_ptr, "too many text chunks",
            PNG_CHUNK_WRITE_ERROR);
-
         return 1;
      }

@@ -919,97 +917,59 @@ png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
   if (png_ptr == NULL || info_ptr == NULL)
      return;

-   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
-      png_chunk_report(png_ptr,
-         "png_set_tRNS: invalid on PNG with alpha channel", PNG_CHUNK_ERROR);
-
-   else if (info_ptr->color_type & PNG_COLOR_MASK_PALETTE)
+   if (trans_alpha != NULL)
   {
-      int max_num;
+       /* It may not actually be necessary to set png_ptr->trans_alpha here;
+        * we do it for backward compatibility with the way the png_handle_tRNS
+        * function used to do the allocation.
+        *
+        * 1.6.0: The above statement is incorrect; png_handle_tRNS effectively
+        * relies on png_set_tRNS storing the information in png_struct
+        * (otherwise it won't be there for the code in pngrtran.c).
+        */

-      /* Free the old data; num_trans 0 can be used to kill the tRNS */
-      png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
+       png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);

-      /* Do this just in case the old data was not owned by libpng: */
-      info_ptr->valid &= ~PNG_INFO_tRNS;
-      info_ptr->trans_alpha = NULL;
-      info_ptr->num_trans = 0;
+       /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
+       png_ptr->trans_alpha = info_ptr->trans_alpha = png_voidcast(png_bytep,
+         png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));

-      /* Expect png_set_PLTE to happen before png_set_tRNS, so num_palette will
-       * be set, but this is not a requirement of the API.
-       */
-      if (png_ptr->num_palette)
-         max_num = png_ptr->num_palette;
-
-      else
-         max_num = 1 << png_ptr->bit_depth;
-
-      if (num_trans > max_num)
-      {
-         png_chunk_report(png_ptr, "png_set_tRNS: num_trans too large",
-            PNG_CHUNK_ERROR);
-         /* If control returns simply limit it; the behavior prior to 1.7 was to
-          * issue a warning and skip the palette in png_write_tRNS.
-          */
-         num_trans = max_num;
-      }
-
-      /* But only attempt a malloc if there is something to do; so the app can
-       * set a tRNS array then later delete it.
-       */
-      if (num_trans > 0 && trans_alpha != NULL)
-      {
-         /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1,
-          * this avoids issues where a palette image contains out of range
-          * indices.
-          */
-         info_ptr->trans_alpha = png_voidcast(png_bytep, png_malloc(png_ptr,
-            PNG_MAX_PALETTE_LENGTH));
-         info_ptr->free_me |= PNG_FREE_TRNS;
-
-         memcpy(info_ptr->trans_alpha, trans_alpha,
-            (unsigned)/*SAFE*/num_trans);
-         info_ptr->valid |= PNG_INFO_tRNS;
-         info_ptr->num_trans = (png_uint_16)num_trans; /* SAFE */
-      }
+       if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
+          memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans);
   }

-   else /* not a PALETTE image */
+   if (trans_color != NULL)
   {
-      /* Invalidate any prior transparent color, set num_trans too, it is not
-       * used internally in this case but png_get_tRNS still returns it.
-       */
-      info_ptr->valid &= ~PNG_INFO_tRNS;
-      info_ptr->num_trans = 0; /* for png_get_tRNS */
+      int sample_max = (1 << info_ptr->bit_depth);

-      if (trans_color != NULL)
-      {
-         int sample_max = (1 << info_ptr->bit_depth);
+      if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
+          trans_color->gray > sample_max) ||
+          (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+          (trans_color->red > sample_max ||
+          trans_color->green > sample_max ||
+          trans_color->blue > sample_max)))
+         png_warning(png_ptr,
+            "tRNS chunk has out-of-range samples for bit_depth");

-         if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
-             trans_color->gray <= sample_max) ||
-             (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
-             trans_color->red <= sample_max &&
-             trans_color->green <= sample_max &&
-             trans_color->blue <= sample_max))
-         {
-            info_ptr->trans_color = *trans_color;
-            info_ptr->valid |= PNG_INFO_tRNS;
-            info_ptr->num_trans = 1; /* for png_get_tRNS */
-         }
+      info_ptr->trans_color = *trans_color;

-         else
-            png_chunk_report(png_ptr,
-               "tRNS chunk has out-of-range samples for bit_depth",
-               PNG_CHUNK_ERROR);
-      }
+      if (num_trans == 0)
+         num_trans = 1;
+   }
+
+   info_ptr->num_trans = (png_uint_16)num_trans;
+
+   if (num_trans != 0)
+   {
+      info_ptr->valid |= PNG_INFO_tRNS;
+      info_ptr->free_me |= PNG_FREE_TRNS;
   }
 }
 #endif

 #ifdef PNG_sPLT_SUPPORTED
 void PNGAPI
-png_set_sPLT(png_structrp png_ptr,
+png_set_sPLT(png_const_structrp png_ptr,
    png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)
 /*
 *  entries        - array of png_sPLT_t structures
@@ -1036,7 +996,6 @@ png_set_sPLT(png_structrp png_ptr,
   {
      /* Out of memory or too many chunks */
      png_chunk_report(png_ptr, "too many sPLT chunks", PNG_CHUNK_WRITE_ERROR);
-
      return;
   }

@@ -1145,7 +1104,7 @@ check_location(png_const_structrp png_ptr, int location)
 }

 void PNGAPI
-png_set_unknown_chunks(png_structrp png_ptr,
+png_set_unknown_chunks(png_const_structrp png_ptr,
   png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
 {
   png_unknown_chunkp np;
@@ -1190,7 +1149,6 @@ png_set_unknown_chunks(png_structrp png_ptr,
   {
      png_chunk_report(png_ptr, "too many unknown chunks",
         PNG_CHUNK_WRITE_ERROR);
-
      return;
   }

@@ -1247,6 +1205,8 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
 {
   /* This API is pretty pointless in 1.6.0 because the location can be set
    * before the call to png_set_unknown_chunks.
+    *
+    * TODO: add a png_app_warning in 1.7
    */
   if (png_ptr != NULL && info_ptr != NULL && chunk >= 0 &&
      chunk < info_ptr->unknown_chunks_num)
@@ -1265,10 +1225,6 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
      info_ptr->unknown_chunks[chunk].location =
         check_location(png_ptr, location);
   }
-
-   /* TODO: make this an error in 1.8 (or maybe it will become one in 1.7!) */
-   else if (png_ptr != NULL)
-      png_app_warning(png_ptr, "unknown chunk index out of range");
 }
 #endif

@@ -1569,19 +1525,19 @@ png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max,
    * rejected by png_set_IHDR().  To accept any PNG datastream
    * regardless of dimensions, set both limits to 0x7ffffffL.
    */
-   if (png_ptr != NULL)
-   {
-      png_ptr->user_width_max = user_width_max;
-      png_ptr->user_height_max = user_height_max;
-   }
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->user_width_max = user_width_max;
+   png_ptr->user_height_max = user_height_max;
 }

 /* This function was added to libpng 1.4.0 */
 void PNGAPI
 png_set_chunk_cache_max (png_structrp png_ptr, png_uint_32 user_chunk_cache_max)
 {
-   if (png_ptr != NULL)
-      png_ptr->user_chunk_cache_max = user_chunk_cache_max;
+    if (png_ptr != NULL)
+       png_ptr->user_chunk_cache_max = user_chunk_cache_max;
 }

 /* This function was added to libpng 1.4.1 */
--- a/pngstruct.h
+++ b/pngstruct.h
@@ -1,11 +1,11 @@

 /* pngstruct.h - header file for PNG reference library
 *
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2013 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.)
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.1 [March 28, 2013]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -28,9 +28,7 @@
   /* We must ensure that zlib uses 'const' in declarations. */
 #  define ZLIB_CONST
 #endif
-
-#include PNG_ZLIB_HEADER
-
+#include "zlib.h"
 #ifdef const
   /* zlib.h sometimes #defines const to nothing, undo this. */
 #  undef const
@@ -50,10 +48,10 @@
 /* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
 * can handle at once.  This type need be no larger than 16 bits (so maximum of
 * 65535), this define allows us to discover how big it is, but limited by the
- * maximum for size_t. The value can be overridden in a library build (pngusr.h,
- * or set it in CPPFLAGS) and it works to set it to a considerably lower value
- * (e.g. 255 works).  A lower value may help memory usage (slightly) and may
- * even improve performance on some systems (and degrade it on others.)
+ * maximuum for png_size_t.  The value can be overriden in a library build
+ * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
+ * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
+ * and may even improve performance on some systems (and degrade it on others.)
 */
 #ifndef ZLIB_IO_MAX
 #  define ZLIB_IO_MAX ((uInt)-1)
@@ -139,373 +137,224 @@ typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
 #define PNG_COLORSPACE_FROM_sRGB            0x0020
 #define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
 #define PNG_COLORSPACE_MATCHES_sRGB         0x0080 /* exact match on profile */
-#define PNG_COLORSPACE_RGB_TO_GRAY_SET      0x0100 /* user specified coeffs */
 #define PNG_COLORSPACE_INVALID              0x8000
 #define PNG_COLORSPACE_CANCEL(flags)        (0xffff ^ (flags))
 #endif /* COLORSPACE || GAMMA */

 struct png_struct_def
 {
-   /* Rearranged in libpng 1.7 to attempt to lessen padding; in general
-    * (char), (short), (int) and pointer types are kept separate, however
-    * associated members under the control of the same #define are still
-    * together.
-    */
 #ifdef PNG_SETJMP_SUPPORTED
-   /* jmp_buf can have very high alignment requirements on some systems, so put
-    * it first (the other setjmp members are later as they are infrequently
-    * accesed.)
-    */
-   jmp_buf jmp_buf_local;
+   jmp_buf jmp_buf_local;     /* New name in 1.6.0 for jmp_buf in png_struct */
+   png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
+   jmp_buf *jmp_buf_ptr;      /* passed to longjmp_fn */
+   size_t jmp_buf_size;       /* size of the above, if allocated */
+#endif
+   png_error_ptr error_fn;    /* function for printing errors and aborting */
+#ifdef PNG_WARNINGS_SUPPORTED
+   png_error_ptr warning_fn;  /* function for printing warnings */
+#endif
+   png_voidp error_ptr;       /* user supplied struct for error functions */
+   png_rw_ptr write_data_fn;  /* function for writing output data */
+   png_rw_ptr read_data_fn;   /* function for reading input data */
+   png_voidp io_ptr;          /* ptr to application struct for I/O functions */
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   png_user_transform_ptr read_user_transform_fn; /* user read transform */
 #endif

-   /* Next the frequently accessed fields.  Many processors perform arithmetic
-    * in the address pipeline, but frequently the amount of addition or
-    * subtraction is limited.  By putting these fields at the head of png_struct
-    * the hope is that such processors will generate code that is both smaller
-    * and faster.
-    */
-   png_colorp  palette;        /* palette from the input file */
-   size_t      rowbytes;       /* size of row in bytes */
-   size_t      info_rowbytes;  /* cache of updated row bytes */
-   png_uint_32 width;          /* width of image in pixels */
-   png_uint_32 height;         /* height of image in pixels */
-   png_uint_32 num_rows;       /* number of rows in current pass */
-   png_uint_32 usr_width;      /* width of row at start of write */
-   png_uint_32 iwidth;         /* width of current interlaced row in pixels */
-   png_uint_32 row_number;     /* current row in interlace pass */
-   png_uint_32 chunk_name;     /* PNG_CHUNK() id of current chunk */
-   png_uint_32 crc;            /* current chunk CRC value */
-   png_uint_32 mode;           /* tells us where we are in the PNG file */
-   png_uint_32 flags;          /* flags indicating various things to libpng */
-   png_uint_32 transformations;/* which transformations to perform */
-   png_uint_32 zowner;         /* ID (chunk type) of zstream owner, 0 if none */
-   png_uint_32 free_me;        /* items libpng is responsible for freeing */
-
-   int         maximum_pixel_depth; /* pixel depth used for the row buffers */
-#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
-   int         num_palette_max;     /* maximum palette index found in IDAT */
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+   png_user_transform_ptr write_user_transform_fn; /* user write transform */
 #endif

+/* These were added in libpng-1.0.2 */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+   png_voidp user_transform_ptr; /* user supplied struct for user transform */
+   png_byte user_transform_depth;    /* bit depth of user transformed pixels */
+   png_byte user_transform_channels; /* channels in user transformed pixels */
+#endif
+#endif
+
+   png_uint_32 mode;          /* tells us where we are in the PNG file */
+   png_uint_32 flags;         /* flags indicating various things to libpng */
+   png_uint_32 transformations; /* which transformations to perform */
+
+   png_uint_32 zowner;        /* ID (chunk type) of zstream owner, 0 if none */
+   z_stream    zstream;       /* decompression structure */
+
+#ifdef PNG_WRITE_SUPPORTED
+   png_compression_bufferp zbuffer_list; /* Created on demand during write */
+   uInt                    zbuffer_size; /* size of the actual buffer */
+
+   int zlib_level;            /* holds zlib compression level */
+   int zlib_method;           /* holds zlib compression method */
+   int zlib_window_bits;      /* holds zlib compression window bits */
+   int zlib_mem_level;        /* holds zlib compression memory level */
+   int zlib_strategy;         /* holds zlib compression strategy */
+#endif
+/* Added at libpng 1.5.4 */
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+   int zlib_text_level;            /* holds zlib compression level */
+   int zlib_text_method;           /* holds zlib compression method */
+   int zlib_text_window_bits;      /* holds zlib compression window bits */
+   int zlib_text_mem_level;        /* holds zlib compression memory level */
+   int zlib_text_strategy;         /* holds zlib compression strategy */
+#endif
+/* End of material added at libpng 1.5.4 */
+/* Added at libpng 1.6.0 */
+#ifdef PNG_WRITE_SUPPORTED
+   int zlib_set_level;        /* Actual values set into the zstream on write */
+   int zlib_set_method;
+   int zlib_set_window_bits;
+   int zlib_set_mem_level;
+   int zlib_set_strategy;
+#endif
+
+   png_uint_32 width;         /* width of image in pixels */
+   png_uint_32 height;        /* height of image in pixels */
+   png_uint_32 num_rows;      /* number of rows in current pass */
+   png_uint_32 usr_width;     /* width of row at start of write */
+   png_size_t rowbytes;       /* size of row in bytes */
+   png_uint_32 iwidth;        /* width of current interlaced row in pixels */
+   png_uint_32 row_number;    /* current row in interlace pass */
+   png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
+   png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
+                               * This is a pointer into big_prev_row
+                               */
+   png_bytep row_buf;         /* buffer to save current (unfiltered) row.
+                               * This is a pointer into big_row_buf
+                               */
+#ifdef PNG_WRITE_SUPPORTED
+   png_bytep sub_row;         /* buffer to save "sub" row when filtering */
+   png_bytep up_row;          /* buffer to save "up" row when filtering */
+   png_bytep avg_row;         /* buffer to save "avg" row when filtering */
+   png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
+#endif
+   png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
+
+   png_uint_32 idat_size;     /* current IDAT size for read */
+   png_uint_32 crc;           /* current chunk CRC value */
+   png_colorp palette;        /* palette from the input file */
   png_uint_16 num_palette;   /* number of color entries in palette */
-   png_uint_16 num_trans;     /* number of transparency values */

-   /* Single byte values, typically used either to save space or to hold 1-byte
-    * values from the PNG chunk specifications.
-    */
-   png_byte compression_type; /* file compression type (always 0) */
+/* Added at libpng-1.5.10 */
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   int num_palette_max;       /* maximum palette index found in IDAT */
+#endif
+
+   png_uint_16 num_trans;     /* number of transparency values */
+   png_byte compression;      /* file compression type (always 0) */
   png_byte filter;           /* file filter type (always 0) */
   png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
   png_byte pass;             /* current interlace pass (0 - 6) */
   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
   png_byte color_type;       /* color type of file */
   png_byte bit_depth;        /* bit depth of file */
+   png_byte usr_bit_depth;    /* bit depth of users row: write only */
   png_byte pixel_depth;      /* number of bits per pixel */
   png_byte channels;         /* number of channels in file */
+#ifdef PNG_WRITE_SUPPORTED
+   png_byte usr_channels;     /* channels at start of write: write only */
+#endif
   png_byte sig_bytes;        /* magic bytes read/written from start of file */
+   png_byte maximum_pixel_depth;
+                              /* pixel depth used for the row buffers */
   png_byte transformed_pixel_depth;
                              /* pixel depth after read/write transforms */
-
-   /* ERROR HANDLING */
-#ifdef PNG_SETJMP_SUPPORTED
-   jmp_buf        *jmp_buf_ptr;   /* passed to longjmp_fn */
-   png_longjmp_ptr longjmp_fn;    /* setjmp non-local goto function. */
-   size_t          jmp_buf_size;  /* size of *jmp_buf_ptr, if allocated */
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+   png_uint_16 filler;           /* filler bytes for pixel expansion */
 #endif

-   /* Error/warning callbacks */
-   png_error_ptr error_fn;        /* print an error message and abort */
-#ifdef PNG_WARNINGS_SUPPORTED
-   png_error_ptr warning_fn;      /* print a warning and continue */
-#endif
-   png_voidp     error_ptr;       /* user supplied data for the above */
-
-   /* MEMORY ALLOCATION */
-#ifdef PNG_USER_MEM_SUPPORTED
-   png_malloc_ptr malloc_fn; /* allocate memory */
-   png_free_ptr   free_fn;   /* free memory */
-   png_voidp      mem_ptr;   /* user supplied data for the above */
-#endif
-
-   /* IO and BASIC READ/WRITE SUPPORT */
-   png_voidp            io_ptr;       /* user supplied data for IO callbacks */
-
-#ifdef PNG_READ_SUPPORTED
-   png_rw_ptr          read_data_fn;  /* read some bytes (must succeed) */
-   png_read_status_ptr read_row_fn;   /* called after each row is decoded */
-   png_bytep           read_buffer;   /* buffer for reading chunk data */
-
-   /* During read the following array is set up to point to the appropriate
-    * un-filter function, this allows per-image and per-processor optimization.
-    */
-   void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
-      png_bytep row, png_const_bytep prev_row);
-
-#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
-   /* The png_struct colorspace structure is only required on read - on write it
-    * is in (just) the info_struct.
-    */
-   png_colorspace   colorspace;
-#endif
-#endif /* PNG_READ_SUPPORTED */
-
-#ifdef PNG_SET_USER_LIMITS_SUPPORTED
-   png_uint_32 user_width_max;        /* Maximum width on read */
-   png_uint_32 user_height_max;       /* Maximum height on read */
-   /* Total memory that a single zTXt, sPLT, iTXt, iCCP, or unknown chunk
-    * can occupy when decompressed.  0 means unlimited.  This field is a counter
-    * - it is decremented as memory is allocated.
-    */
-   png_alloc_size_t user_chunk_malloc_max;
-#endif
-#ifdef PNG_USER_LIMITS_SUPPORTED
-   /* limit on total *number* of sPLT, text and unknown chunks that can be
-    * stored.  0 means unlimited.  This field is a counter - it is decremented
-    * as chunks are encountered.
-    */
-   png_uint_32 user_chunk_cache_max;
-#endif
-
-   /* The progressive reader gets passed data and calls application handling
-    * functions when appropriate.
-    */
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-   png_progressive_info_ptr info_fn; /* called after header data fully read */
-   png_progressive_row_ptr  row_fn;  /* called after a row is decoded */
-   png_progressive_end_ptr  end_fn;  /* called after image is complete */
-
-   /* Progressive read control data */
-   png_bytep   save_buffer_ptr;      /* current location in save_buffer */
-   png_bytep   save_buffer;          /* buffer for previously read data */
-   png_bytep   current_buffer_ptr;   /* current location in current_buffer */
-   png_bytep   current_buffer;       /* buffer for recently used data */
-
-   size_t      save_buffer_size;     /* amount of data now in save_buffer */
-   size_t      save_buffer_max;      /* total size of save_buffer */
-   size_t      buffer_size;          /* total amount of available input data */
-   size_t      current_buffer_size;  /* amount of data now in current_buffer */
-
-   png_uint_32 push_length;          /* size of current input chunk */
-   png_uint_32 skip_length;          /* bytes to skip in input data */
-
-   int         process_mode;         /* what push library is currently doing */
-   int         cur_palette;          /* current push library palette index */
-#endif
-
-#ifdef PNG_WRITE_SUPPORTED
-   png_rw_ptr              write_data_fn;/* write some bytes (must succeed) */
-   png_write_status_ptr    write_row_fn; /* called after each row is encoded */
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+   png_byte background_gamma_type;
+   png_fixed_point background_gamma;
+   png_color_16 background;   /* background color in screen gamma space */
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   png_color_16 background_1; /* background normalized to gamma 1.0 */
 #endif
+#endif /* PNG_bKGD_SUPPORTED */

 #ifdef PNG_WRITE_FLUSH_SUPPORTED
   png_flush_ptr output_flush_fn; /* Function for flushing output */
-   png_uint_32   flush_dist; /* how many rows apart to flush, 0 - no flush */
-   png_uint_32   flush_rows; /* number of rows written since last flush */
+   png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
+   png_uint_32 flush_rows;    /* number of rows written since last flush */
 #endif

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   png_bytep    prev_filters;        /* filter type(s) of previous row(s) */
-   png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
-   png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
-   png_uint_16p filter_costs;        /* relative filter calculation cost */
-   png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
-   png_byte     heuristic_method;    /* heuristic for row filter selection */
-   png_byte     num_prev_filters;    /* number of weights for previous rows */
-#endif
-
-#ifdef PNG_WRITE_SUPPORTED
-   png_byte     usr_bit_depth;       /* bit depth of users row */
-   png_byte     usr_channels;        /* channels at start of write */
-#endif
-
-#ifdef PNG_IO_STATE_SUPPORTED
-   png_uint_32          io_state;     /* tells the app read/write progress */
-#endif
-
-   /* ROW BUFFERS
-    *
-    * Members that hold pointers to the decompressed image rows.
-    */
-   png_bytep row_buf;  /* buffer for the current (unfiltered) row */
-#if defined(PNG_WRITE_FILTER_SUPPORTED) || defined(PNG_READ_SUPPORTED)
-   png_bytep prev_row; /* buffer to save the previous (unfiltered) row */
-#endif
-
-#ifdef PNG_READ_SUPPORTED
-   /* The row_buf and prev_row pointers are misaligned so that the start of the
-    * row - after the filter byte - is aligned, the 'big_' pointers record the
-    * original allocated pointer.
-    */
-   png_bytep big_row_buf;
-   png_bytep big_prev_row;
-   size_t    big_row_buf_size; /* Actual size of both */
-#endif
-
-#ifdef PNG_WRITE_SUPPORTED
-   /* This is somewhat excessive, there is no obvious reason on write to
-    * allocate a buffer for each possible filtered row, only for the one being
-    * tested and the current best.
-    *
-    * TODO: fix this
-    */
-   png_bytep sub_row;         /* buffer to save "sub" row when filtering */
-   png_bytep up_row;          /* buffer to save "up" row when filtering */
-   png_bytep avg_row;         /* buffer to save "avg" row when filtering */
-   png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
-#endif
-
-   /* UNKNOWN CHUNK HANDLING */
-   /* TODO: this is excessively complicated, there are multiple ways of doing
-    * the same thing.  It should be cleaned up, possibly by finding out which
-    * APIs applications really use.
-    */
-#ifdef PNG_USER_CHUNKS_SUPPORTED
-   /* General purpose pointer for all user/unknown chunk handling; points to
-    * application supplied data for use in the read_user_chunk_fn callback
-    * (currently there is no write side support - the write side must use the
-    * set_unknown_chunks interface.)
-    */
-   png_voidp user_chunk_ptr;
-#endif
-
-#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
-   /* This is called back from the unknown chunk handling */
-   png_user_chunk_ptr     read_user_chunk_fn; /* user read chunk handler */
-#endif
-#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
-   /* Temporary storage for unknown chunk that the library doesn't recognize,
-    * used while reading the chunk.
-    */
-   png_unknown_chunk unknown_chunk;
-#endif
-
-#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
-   png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
-                                  * followed by a PNG_HANDLE_* byte */
-   int          unknown_default; /* As PNG_HANDLE_* */
-   unsigned int num_chunk_list;  /* Number of entries in the list */
-#endif
-
-   /* USER TRANSFORM SUPPORT */
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-   png_user_transform_ptr read_user_transform_fn; /* user read transform */
-#endif
-#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
-   png_user_transform_ptr write_user_transform_fn; /* user write transform */
-#endif
-#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-   png_voidp user_transform_ptr;      /* user supplied data for the above */
-   png_byte  user_transform_depth;    /* bit depth of user transformed pixels */
-   png_byte  user_transform_channels; /* channels in user transformed pixels */
-#endif
-
-   /* READ TRANSFORM SUPPORT
-    *
-    * Quite a lot of things can be done to the original image data on read, and
-    * most of these are configurable.  The data required by the configurable
-    * read transforms should be stored here.  The png_color_16 and png_color_8
-    * structures have low alignment requirements and odd sizes, so may cause
-    * misalignment when present.  Member alignment is as follows:
-    *
-    *    png_color_16   png_uint_16
-    *    png_color_8    png_byte
-    */
-   /* GAMMA/BACKGROUND/ALPHA-MODE/RGB-TO-GRAY/tRNS/sBIT
-    *
-    * These things are all interrelated because they need some or all of the
-    * gamma tables.  Some attempt has been made below to order these members by
-    * size, so that as little padding as possible is required.
-    */
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   png_bytep gamma_table;        /* gamma table for 8-bit depth files */
-   png_uint_16p gamma_16_table;  /* gamma table for 16-bit depth files */
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED) ||\
-   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-   png_bytep gamma_from_1;       /* converts from 1.0 to screen */
-   png_uint_16p gamma_to_1;      /* converts from file to 1.0 */
-   png_uint_16p gamma_16_from_1; /* converts from 1.0 to screen */
-   png_uint_16p gamma_16_to_1;   /* converts from file to 1.0 */
-#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
-#endif /* PNG_READ_GAMMA_SUPPORTED */
-
-#if defined(PNG_READ_tRNS_SUPPORTED) || \
-   defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_EXPAND_SUPPORTED)
-   png_bytep trans_alpha;           /* alpha values for paletted files */
-#endif
-
-   /* Integer values */
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   png_fixed_point background_gamma;
-#endif
 #ifdef PNG_READ_GAMMA_SUPPORTED
+   int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
   png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
-   int gamma_shift; /* number of "insignificant" bits in 16-bit gamma */
+
+   png_bytep gamma_table;     /* gamma table for 8-bit depth files */
+   png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+   png_bytep gamma_from_1;    /* converts from 1.0 to screen */
+   png_bytep gamma_to_1;      /* converts from file to 1.0 */
+   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
+   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
 #endif

-   /* png_color_16 */
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   png_color_16 background;   /* background color in screen gamma space */
-   png_color_16 background_1; /* background normalized to gamma 1.0 */
-#endif
-#if defined(PNG_READ_tRNS_SUPPORTED) || \
-   defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_EXPAND_SUPPORTED)
-   png_color_16 trans_color;  /* transparent color for non-paletted files */
-#endif
-
-   /* png_uint_16 */
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   png_uint_16 rgb_to_gray_red_coeff;
-   png_uint_16 rgb_to_gray_green_coeff;
-   /* The blue coefficient is calculated from the above */
-#endif
-
-   /* png_color_8 */
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_sBIT_SUPPORTED)
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
   png_color_8 sig_bit;       /* significant bits in each available channel */
 #endif

-   /* png_byte */
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   png_byte background_gamma_type;
-#endif
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   png_byte rgb_to_gray_status;
-#endif
-
-   /* SHIFT - both READ_SHIFT and WRITE_SHIFT */
 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
   png_color_8 shift;         /* shift for significant bit tranformation */
 #endif

-   /* FILLER SUPPORT (pixel expansion or read, contraction on write) */
-#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
-   png_uint_16 filler;              /* filler bytes for pixel expansion */
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
+ || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_bytep trans_alpha;           /* alpha values for paletted files */
+   png_color_16 trans_color;  /* transparent color for non-paletted files */
+#endif
+
+   png_read_status_ptr read_row_fn;   /* called after each row is decoded */
+   png_write_status_ptr write_row_fn; /* called after each row is encoded */
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+   png_progressive_info_ptr info_fn; /* called after header data fully read */
+   png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
+   png_progressive_end_ptr end_fn;   /* called after image is complete */
+   png_bytep save_buffer_ptr;        /* current location in save_buffer */
+   png_bytep save_buffer;            /* buffer for previously read data */
+   png_bytep current_buffer_ptr;     /* current location in current_buffer */
+   png_bytep current_buffer;         /* buffer for recently used data */
+   png_uint_32 push_length;          /* size of current input chunk */
+   png_uint_32 skip_length;          /* bytes to skip in input data */
+   png_size_t save_buffer_size;      /* amount of data now in save_buffer */
+   png_size_t save_buffer_max;       /* total size of save_buffer */
+   png_size_t buffer_size;           /* total amount of available input data */
+   png_size_t current_buffer_size;   /* amount of data now in current_buffer */
+   int process_mode;                 /* what push library is currently doing */
+   int cur_palette;                  /* current push library palette index */
+
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+
+#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
+/* For the Borland special 64K segment handler */
+   png_bytepp offset_table_ptr;
+   png_bytep offset_table;
+   png_uint_16 offset_table_number;
+   png_uint_16 offset_table_count;
+   png_uint_16 offset_table_count_free;
 #endif

-   /* QUANTIZE (convert to color-mapped) */
 #ifdef PNG_READ_QUANTIZE_SUPPORTED
-   png_bytep palette_lookup;   /* lookup table for quantizing */
-   png_bytep quantize_index;   /* index translation for palette files */
-   png_bytep quantize_sort;    /* working sort array */
-   png_bytep index_to_palette; /* where the original index currently is in the
-                                * palette
-                                */
-   png_bytep palette_to_index; /* which original index points to this palette
-                                * color
-                                */
+   png_bytep palette_lookup; /* lookup table for quantizing */
+   png_bytep quantize_index; /* index translation for palette files */
 #endif

-   /* MNG SUPPORT */
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-   png_uint_32 mng_features_permitted;
-   png_byte filter_type;
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+   png_byte heuristic_method;        /* heuristic for row filter selection */
+   png_byte num_prev_filters;        /* number of weights for previous rows */
+   png_bytep prev_filters;           /* filter type(s) of previous row(s) */
+   png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
+   png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
+   png_uint_16p filter_costs;        /* relative filter calculation cost */
+   png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
 #endif

   /* Options */
@@ -513,48 +362,128 @@ struct png_struct_def
   png_byte options;           /* On/off state (up to 4 options) */
 #endif

-   /* COMPRESSION AND DECOMPRESSION SUPPORT.
-    *
-    * zlib expects a 'zstream' as the fundamental control structure, it allows
-    * all the parameters to be passed as one pointer.
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng-1.7 */
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+   char time_buffer[29]; /* String to hold RFC 1123 time text */
+#endif
+#endif
+
+/* New members added in libpng-1.0.6 */
+
+   png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+   png_voidp user_chunk_ptr;
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
+#endif
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   int          unknown_default; /* As PNG_HANDLE_* */
+   unsigned int num_chunk_list;  /* Number of entries in the list */
+   png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
+                                  * followed by a PNG_HANDLE_* byte */
+#endif
+
+/* New members added in libpng-1.0.3 */
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   png_byte rgb_to_gray_status;
+   /* Added in libpng 1.5.5 to record setting of coefficients: */
+   png_byte rgb_to_gray_coefficients_set;
+   /* These were changed from png_byte in libpng-1.0.6 */
+   png_uint_16 rgb_to_gray_red_coeff;
+   png_uint_16 rgb_to_gray_green_coeff;
+   /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
+#endif
+
+/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+/* Changed from png_byte to png_uint_32 at version 1.2.0 */
+   png_uint_32 mng_features_permitted;
+#endif
+
+/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   png_byte filter_type;
+#endif
+
+/* New members added in libpng-1.2.0 */
+
+/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_voidp mem_ptr;             /* user supplied struct for mem functions */
+   png_malloc_ptr malloc_fn;      /* function for allocating memory */
+   png_free_ptr free_fn;          /* function for freeing memory */
+#endif
+
+/* New member added in libpng-1.0.13 and 1.2.0 */
+   png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* The following three members were added at version 1.0.14 and 1.2.4 */
+   png_bytep quantize_sort;          /* working sort array */
+   png_bytep index_to_palette;       /* where the original index currently is
+                                        in the palette */
+   png_bytep palette_to_index;       /* which original index points to this
+                                         palette color */
+#endif
+
+/* New members added in libpng-1.0.16 and 1.2.6 */
+   png_byte compression_type;
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   png_uint_32 user_width_max;
+   png_uint_32 user_height_max;
+
+   /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
+    * chunks that can be stored (0 means unlimited).
    */
-   z_stream    zstream;       /* decompression structure */
+   png_uint_32 user_chunk_cache_max;
+
+   /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
+    * can occupy when decompressed.  0 means unlimited.
+    */
+   png_alloc_size_t user_chunk_malloc_max;
+#endif
+
+/* New member added in libpng-1.0.25 and 1.2.17 */
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+   /* Temporary storage for unknown chunk that the library doesn't recognize,
+    * used while reading the chunk.
+    */
+   png_unknown_chunk unknown_chunk;
+#endif
+
+/* New member added in libpng-1.2.26 */
+  png_size_t old_big_row_buf_size;

 #ifdef PNG_READ_SUPPORTED
-   /* These, and IDAT_read_size below, control how much input and output (at
-    * most) is available to zlib.
-    */
-   png_uint_32      idat_size;        /* current IDAT size for read */
-   png_alloc_size_t read_buffer_size; /* current size of the buffer */
+/* New member added in libpng-1.2.30 */
+  png_bytep        read_buffer;      /* buffer for reading chunk data */
+  png_alloc_size_t read_buffer_size; /* current size of the buffer */
 #endif
-
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
-   int zlib_text_level;       /* holds zlib compression level */
-   int zlib_text_method;      /* holds zlib compression method */
-   int zlib_text_window_bits; /* holds zlib compression window bits */
-   int zlib_text_mem_level;   /* holds zlib compression memory level */
-   int zlib_text_strategy;    /* holds zlib compression strategy */
-#endif
-
-#ifdef PNG_WRITE_SUPPORTED
-   int zlib_level;            /* holds zlib compression level */
-   int zlib_method;           /* holds zlib compression method */
-   int zlib_window_bits;      /* holds zlib compression window bits */
-   int zlib_mem_level;        /* holds zlib compression memory level */
-   int zlib_strategy;         /* holds zlib compression strategy */
-
-   int zlib_set_level;        /* Actual values set into the zstream on write */
-   int zlib_set_method;
-   int zlib_set_window_bits;
-   int zlib_set_mem_level;
-   int zlib_set_strategy;
-
-   png_compression_bufferp zbuffer_list; /* Created on demand during write */
-   uInt                    zbuffer_size; /* size of the actual zlib buffer */
-#endif
-
 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-   uInt IDAT_read_size;       /* limit on read buffer size for IDAT */
+  uInt             IDAT_read_size;   /* limit on read buffer size for IDAT */
+#endif
+
+#ifdef PNG_IO_STATE_SUPPORTED
+/* New member added in libpng-1.4.0 */
+   png_uint_32 io_state;
+#endif
+
+/* New member added in libpng-1.5.6 */
+   png_bytep big_prev_row;
+
+/* New member added in libpng-1.5.7 */
+   void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
+      png_bytep row, png_const_bytep prev_row);
+
+#ifdef PNG_READ_SUPPORTED
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+   png_colorspace   colorspace;
+#endif
 #endif
 };
 #endif /* PNGSTRUCT_H */
--- a/pngtest.c
+++ b/pngtest.c
@@ -1991,4 +1991,4 @@ main(void)
 #endif

 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_7_0beta34 Your_png_h_is_not_version_1_7_0beta34;
+typedef png_libpng_version_1_6_11beta02 Your_png_h_is_not_version_1_6_11beta02;
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -327,9 +327,13 @@ png_do_swap(png_row_infop row_info, png_bytep row)

      for (i = 0; i < istop; i++, rp += 2)
      {
+#ifdef PNG_BUILTIN_BSWAP16_SUPPORTED
+         *(png_uint_16*)rp = __builtin_bswap16(*(png_uint_16*)rp);
+#else
         png_byte t = *rp;
         *rp = *(rp + 1);
         *(rp + 1) = t;
+#endif
      }
   }
 }
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,7 +1,7 @@

 /* pngwrite.c - general routines to write a PNG file
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.11 [(PENDING RELEASE)]
 * 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.)
@@ -216,13 +216,8 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
      if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
          info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      {
-         int j, jend;
-
-         jend = info_ptr->num_trans;
-         if (jend > PNG_MAX_PALETTE_LENGTH)
-            jend = PNG_MAX_PALETTE_LENGTH;
-
-         for (j = 0; j<jend; ++j)
+         int j;
+         for (j = 0; j<(int)info_ptr->num_trans; j++)
            info_ptr->trans_alpha[j] =
               (png_byte)(255 - info_ptr->trans_alpha[j]);
      }
@@ -437,6 +432,7 @@ 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
@@ -484,7 +480,7 @@ 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);
@@ -497,9 +493,8 @@ 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);
+       error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
 #endif /* PNG_USER_MEM_SUPPORTED */
-
   if (png_ptr != NULL)
   {
      /* Set the zlib control values to defaults; they can be overridden by the
@@ -531,17 +526,17 @@ 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
       * are errors during development.
       */
 #if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
-         png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
+      png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
 #endif

      /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
@@ -1000,52 +995,42 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
       (method == PNG_INTRAPIXEL_DIFFERENCING))
      method = PNG_FILTER_TYPE_BASE;
+
 #endif
-
-   /* The only supported method, except for the check above, is
-    * PNG_FILTER_TYPE_BASE.  The code below does not use 'method' other than
-    * for the check, so just keep going if png_app_error returns.
-    */
-   if (method != PNG_FILTER_TYPE_BASE)
-      png_app_error(png_ptr, "Unknown custom filter method");
-
-   /* If filter writing is not supported the 'filters' value must be zero,
-    * otherwise the value must be a single, valid, filter value or a set of the
-    * mask values.  The defines in png.h are such that the filter masks used in
-    * this API and internally are 1<<(3+value), value is in the range 0..4, so
-    * this fits in a byte.
-    */
-#  ifdef PNG_WRITE_FILTER_SUPPORTED
-      /* Notice that PNG_NO_FILTERS is 0 and passes this test; this is OK
-       * because filters then gets set to PNG_FILTER_NONE, as is required.
-       */
-      if (filters < PNG_FILTER_VALUE_LAST)
-         filters = 0x08 << filters;
-
-      else if ((filters & ~PNG_ALL_FILTERS) != 0)
+   if (method == PNG_FILTER_TYPE_BASE)
+   {
+      switch (filters & (PNG_ALL_FILTERS | 0x07))
      {
-         png_app_error(png_ptr, "png_set_filter: invalid filters mask/value");
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         case 5:
+         case 6:
+         case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
+            /* FALL THROUGH */
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
+         case PNG_FILTER_VALUE_NONE:
+            png_ptr->do_filter = PNG_FILTER_NONE; break;

-         /* For compatibility with the previous behavior assume a mask value was
-          * passed and ignore the non-mask bits.
-          */
-         filters &= PNG_ALL_FILTERS;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         case PNG_FILTER_VALUE_SUB:
+            png_ptr->do_filter = PNG_FILTER_SUB; break;

-         /* For a possibly foolish consistency (it shouldn't matter) set
-          * PNG_FILTER_NONE rather than 0.
-          */
-         if (filters == 0)
-            filters = PNG_FILTER_NONE;
+         case PNG_FILTER_VALUE_UP:
+            png_ptr->do_filter = PNG_FILTER_UP; break;
+
+         case PNG_FILTER_VALUE_AVG:
+            png_ptr->do_filter = PNG_FILTER_AVG; break;
+
+         case PNG_FILTER_VALUE_PAETH:
+            png_ptr->do_filter = PNG_FILTER_PAETH; break;
+
+         default:
+            png_ptr->do_filter = (png_byte)filters; break;
+#else
+         default:
+            png_app_error(png_ptr, "Unknown row filter for method 0");
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
      }
-#  else
-      /* PNG_FILTER_VALUE_NONE and PNG_NO_FILTERS are both 0. */
-      if (filters != 0 && filters != PNG_FILTER_NONE)
-         png_app_error(png_ptr, "png_set_filter: no filters supported");

-      filters = PNG_FILTER_NONE;
-#  endif
-
-#  ifdef PNG_WRITE_FILTER_SUPPORTED
      /* If we have allocated the row_buf, this means we have already started
       * with the image and we should have allocated all of the filter buffers
       * that have been selected.  If prev_row isn't already allocated, then
@@ -1054,45 +1039,75 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
       * wants to start and stop using particular filters during compression,
       * it should start out with all of the filters, and then add and
       * remove them after the start of compression.
-       *
-       * NOTE: this is a nasty constraint on the code, because it means that the
-       * prev_row buffer must be maintained even if there are currently no
-       * 'prev_row' requiring filters active.
       */
      if (png_ptr->row_buf != NULL)
      {
-         /* Repeat the checks in png_write_start_row; 1 pixel high or wide
-          * images cannot benefit from certain filters.  If this isn't done here
-          * the check below will fire on 1 pixel high images.
-          */
-         if (png_ptr->height == 1)
-            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
-
-         if (png_ptr->width == 1)
-            filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
-
-         if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
-            && png_ptr->prev_row == NULL)
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
         {
-            /* This is the error case, however it is benign - the previous row
-             * is not available so the filter can't be used.  Just warn here.
-             */
-            png_app_warning(png_ptr,
-               "png_set_filter: UP/AVG/PAETH cannot be added after start");
-            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
+                (png_ptr->rowbytes + 1));
+            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
         }

-         /* Allocate any required buffers that have not already been allocated.
-          */
-         png_write_alloc_filter_row_buffers(png_ptr, filters);
-      }
-#  endif /* PNG_WRITE_FILTER_SUPPORTED */
+         if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
+         {
+            if (png_ptr->prev_row == NULL)
+            {
+               png_warning(png_ptr, "Can't add Up filter after starting");
+               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
+                   ~PNG_FILTER_UP);
+            }

-   /* Finally store the value.
-    * TODO: this field could probably be removed if neither READ nor
-    * WRITE_FILTER are supported.
-    */
-   png_ptr->do_filter = (png_byte)filters; /* SAFE: checked above */
+            else
+            {
+               png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
+                   (png_ptr->rowbytes + 1));
+               png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
+            }
+         }
+
+         if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
+         {
+            if (png_ptr->prev_row == NULL)
+            {
+               png_warning(png_ptr, "Can't add Average filter after starting");
+               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
+                   ~PNG_FILTER_AVG);
+            }
+
+            else
+            {
+               png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
+                   (png_ptr->rowbytes + 1));
+               png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
+            }
+         }
+
+         if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
+             png_ptr->paeth_row == NULL)
+         {
+            if (png_ptr->prev_row == NULL)
+            {
+               png_warning(png_ptr, "Can't add Paeth filter after starting");
+               png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
+            }
+
+            else
+            {
+               png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
+                   (png_ptr->rowbytes + 1));
+               png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
+            }
+         }
+
+         if (png_ptr->do_filter == PNG_NO_FILTERS)
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
+            png_ptr->do_filter = PNG_FILTER_NONE;
+      }
+   }
+   else
+      png_error(png_ptr, "Unknown custom filter method");
 }

 /* This allows us to influence the way in which libpng chooses the "best"
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@

 /* pngwutil.c - utilities to write a PNG file
 *
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.11 [(PENDING RELEASE)]
 * 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.)
@@ -1425,11 +1425,10 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,

   if (color_type == PNG_COLOR_TYPE_PALETTE)
   {
-      if (num_trans <= 0 || num_trans > png_ptr->num_palette)
+      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
      {
-         /* This is an error which can only be reliably detected late. */
-         png_app_error(png_ptr,
-            "Invalid number of transparent colors specified");
+         png_app_warning(png_ptr,
+             "Invalid number of transparent colors specified");
         return;
      }

@@ -1443,8 +1442,7 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
      /* One 16 bit value */
      if (tran->gray >= (1 << png_ptr->bit_depth))
      {
-         /* This can no longer happen because it is checked in png_set_tRNS */
-         png_app_error(png_ptr,
+         png_app_warning(png_ptr,
             "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");

         return;
@@ -1466,8 +1464,7 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
      if (buf[0] | buf[2] | buf[4])
 #endif
      {
-         /* Also checked in png_set_tRNS */
-         png_app_error(png_ptr,
+         png_app_warning(png_ptr,
           "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
         return;
      }
@@ -1477,8 +1474,7 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,

   else
   {
-      /* Checked in png_set_tRNS */
-      png_app_error(png_ptr, "Can't write tRNS with an alpha channel");
+      png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
   }
 }
 #endif
@@ -1765,7 +1761,7 @@ png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
      png_write_compressed_data_out(png_ptr, &comp);

   else
-      png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.output_len);
+      png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.input_len);

   png_write_chunk_end(png_ptr);
 }
@@ -1938,47 +1934,6 @@ png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)
 }
 #endif

-#ifdef PNG_WRITE_FILTER_SUPPORTED
-void /* PRIVATE */
-png_write_alloc_filter_row_buffers(png_structrp png_ptr, int filters)
-   /* Allocate row buffers for any filters that need them, this is also called
-    * from png_set_filter if the filters are changed during write to ensure that
-    * the required buffers exist.  png_set_filter ensures that up/avg/paeth are
-    * only set if png_ptr->prev_row is allocated.
-    */
-{
-   /* The buffer size is determined just by the output row size, not any
-    * processing requirements.
-    */
-   png_alloc_size_t buf_size = png_ptr->rowbytes + 1;
-
-   if ((filters & PNG_FILTER_SUB) != 0 && png_ptr->sub_row == NULL)
-   {
-      png_ptr->sub_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
-      png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
-   }
-
-   if ((filters & PNG_FILTER_UP) != 0 && png_ptr->up_row == NULL)
-   {
-      png_ptr->up_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
-      png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
-   }
-
-   if ((filters & PNG_FILTER_AVG) != 0 && png_ptr->avg_row == NULL)
-   {
-      png_ptr->avg_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
-      png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
-   }
-
-   if ((filters & PNG_FILTER_PAETH) != 0 && png_ptr->paeth_row == NULL)
-   {
-      png_ptr->paeth_row = png_voidcast(png_bytep, png_malloc(png_ptr,
-         buf_size));
-      png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
-   }
-}
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
-
 /* Initializes the row writing capability of libpng */
 void /* PRIVATE */
 png_write_start_row(png_structrp png_ptr)
@@ -1999,18 +1954,11 @@ png_write_start_row(png_structrp png_ptr)
   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 #endif

-#ifdef PNG_WRITE_FILTER_SUPPORTED
-   int filters;
-#endif
-
   png_alloc_size_t buf_size;
   int usr_pixel_depth;

   png_debug(1, "in png_write_start_row");

-   if (png_ptr == NULL)
-      return;
-
   usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
   buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;

@@ -2019,34 +1967,49 @@ png_write_start_row(png_structrp png_ptr)
   png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;

   /* Set up row buffer */
-   png_ptr->row_buf = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
+   png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size);

   png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;

 #ifdef PNG_WRITE_FILTER_SUPPORTED
-   filters = png_ptr->do_filter;
+   /* Set up filtering buffer, if using this filter */
+   if (png_ptr->do_filter & PNG_FILTER_SUB)
+   {
+      png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1);

-   if (png_ptr->height == 1)
-      filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+      png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
+   }

-   if (png_ptr->width == 1)
-      filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+   /* 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))
+   {
+      /* Set up previous row buffer */
+      png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);

-   if (filters == 0)
-      filters = PNG_FILTER_NONE;
+      if (png_ptr->do_filter & PNG_FILTER_UP)
+      {
+         png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
+            png_ptr->rowbytes + 1);

-   /* We only need to keep the previous row if we are using one of the following
-    * filters.
-    */
-   if (filters & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
-      png_ptr->prev_row = png_voidcast(png_bytep, png_calloc(png_ptr,
-         buf_size));
+         png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
+      }

-   png_write_alloc_filter_row_buffers(png_ptr, filters);
+      if (png_ptr->do_filter & PNG_FILTER_AVG)
+      {
+         png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
+             png_ptr->rowbytes + 1);

-   png_ptr->do_filter = (png_byte)filters; /* in case it was changed above */
-#else
-   png_ptr->do_filter = PNG_FILTER_NONE;
+         png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
+      }
+
+      if (png_ptr->do_filter & PNG_FILTER_PAETH)
+      {
+         png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
+             png_ptr->rowbytes + 1);
+
+         png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
+      }
+   }
 #endif /* PNG_WRITE_FILTER_SUPPORTED */

 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
@@ -2346,7 +2309,8 @@ 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)
@@ -3034,7 +2998,6 @@ png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,

   png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);

-#ifdef PNG_WRITE_FILTER_SUPPORTED
   /* Swap the current and previous rows */
   if (png_ptr->prev_row != NULL)
   {
@@ -3044,7 +3007,6 @@ png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
      png_ptr->prev_row = png_ptr->row_buf;
      png_ptr->row_buf = tptr;
   }
-#endif /* PNG_WRITE_FILTER_SUPPORTED */

   /* Finish row - updates counters and flushes zlib if last row */
   png_write_finish_row(png_ptr);
--- a/projects/visualc71/libpng.vcproj
+++ b/projects/visualc71/libpng.vcproj
@@ -30,7 +30,7 @@
 				Name="VCCustomBuildTool"/>
 			<Tool
 				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/libpng17.dll"
+				OutputFile="$(OutDir)/libpng16.dll"
 				LinkIncremental="1"/>
 			<Tool
 				Name="VCMIDLTool"/>
@@ -78,7 +78,7 @@
 				Name="VCCustomBuildTool"/>
 			<Tool
 				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/libpng17d.dll"
+				OutputFile="$(OutDir)/libpng16d.dll"
 				GenerateDebugInformation="TRUE"/>
 			<Tool
 				Name="VCMIDLTool"/>
@@ -126,7 +126,7 @@
 				Name="VCCustomBuildTool"/>
 			<Tool
 				Name="VCLinkerTool"
-				OutputFile="$(OutDir)/libpng17vb.dll"
+				OutputFile="$(OutDir)/libpng16vb.dll"
 				LinkIncremental="1"/>
 			<Tool
 				Name="VCMIDLTool"/>
--- a/projects/visualc71/pngtest.vcproj
+++ b/projects/visualc71/pngtest.vcproj
@@ -130,7 +130,7 @@ $(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
 				Name="VCLinkerTool"
 				OutputFile="$(OutDir)/pngtest.exe"
 				LinkIncremental="1"
-				IgnoreDefaultLibraryNames="$(IntDir)\libpng17b.lib"
+				IgnoreDefaultLibraryNames="$(IntDir)\libpng16b.lib"
 				SubSystem="1"
 				TargetMachine="1"/>
 			<Tool
--- a/projects/vstudio/libpng/libpng.vcxproj
+++ b/projects/vstudio/libpng/libpng.vcxproj
@@ -63,23 +63,23 @@
    <LinkIncremental>false</LinkIncremental>
    <CustomBuildBeforeTargets>
    </CustomBuildBeforeTargets>
-    <TargetName>$(ProjectName)17</TargetName>
+    <TargetName>$(ProjectName)16</TargetName>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
    <LinkIncremental>false</LinkIncremental>
    <CustomBuildBeforeTargets />
-    <TargetName>$(ProjectName)17</TargetName>
+    <TargetName>$(ProjectName)16</TargetName>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <LinkIncremental>false</LinkIncremental>
    <CustomBuildBeforeTargets>
    </CustomBuildBeforeTargets>
-    <TargetName>$(ProjectName)17</TargetName>
+    <TargetName>$(ProjectName)16</TargetName>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
    <LinkIncremental>false</LinkIncremental>
    <CustomBuildBeforeTargets />
-    <TargetName>$(ProjectName)17</TargetName>
+    <TargetName>$(ProjectName)16</TargetName>
  </PropertyGroup>
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <ClCompile>
@@ -107,7 +107,7 @@
      <SubSystem>Windows</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <AdditionalDependencies>zlib.lib</AdditionalDependencies>
-      <Version>17</Version>
+      <Version>16</Version>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
  </ItemDefinitionGroup>
@@ -164,7 +164,7 @@
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
      <AdditionalDependencies>zlib.lib</AdditionalDependencies>
-      <Version>17</Version>
+      <Version>16</Version>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
  </ItemDefinitionGroup>
--- a/projects/vstudio/pngstest/pngstest.vcxproj
+++ b/projects/vstudio/pngstest/pngstest.vcxproj
@@ -96,7 +96,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -129,7 +129,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -163,7 +163,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
@@ -199,7 +199,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
--- a/projects/vstudio/pngtest/pngtest.vcxproj
+++ b/projects/vstudio/pngtest/pngtest.vcxproj
@@ -96,7 +96,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -129,7 +129,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -164,7 +164,7 @@
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -199,7 +199,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
--- a/projects/vstudio/pngunknown/pngunknown.vcxproj
+++ b/projects/vstudio/pngunknown/pngunknown.vcxproj
@@ -96,7 +96,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -129,7 +129,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -163,7 +163,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
@@ -199,7 +199,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
--- a/projects/vstudio/pngvalid/pngvalid.vcxproj
+++ b/projects/vstudio/pngvalid/pngvalid.vcxproj
@@ -96,7 +96,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -129,7 +129,7 @@
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
    </Link>
    <CustomBuildStep>
@@ -163,7 +163,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
@@ -199,7 +199,7 @@
      <GenerateDebugInformation>true</GenerateDebugInformation>
      <EnableCOMDATFolding>true</EnableCOMDATFolding>
      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng17.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng16.lib;zlib.lib</AdditionalDependencies>
      <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
      <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
    </Link>
--- a/projects/vstudio/readme.txt
+++ b/projects/vstudio/readme.txt
@@ -1,7 +1,7 @@

 VisualStudio instructions

-libpng version 1.7.0beta34 - March 17, 2014
+libpng version 1.6.11beta02 - April 6, 2014

 Copyright (c) 1998-2010 Glenn Randers-Pehrson

@@ -40,7 +40,7 @@ problems.

 If you don't use the Visual Studio defaults your application must still be built
 with the default runtime option (/MD).  If, for some reason, it is not then your
-application will crash inside libpng17.dll as soon as libpng tries to read
+application will crash inside libpng16.dll as soon as libpng tries to read
 from a file handle you pass in.

 If you do not want to use the DLL, for example for a very small application,
--- a/projects/vstudio/zlib.props
+++ b/projects/vstudio/zlib.props
@@ -2,7 +2,7 @@
 <!--
 * zlib.props - location of zlib source
 *
- * libpng version 1.7.0beta34 - March 17, 2014
+ * libpng version 1.6.11beta02 - April 6, 2014
 *
 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
 *
--- a/scripts/README.txt
+++ b/scripts/README.txt
@@ -1,9 +1,9 @@

-Makefiles for  libpng version 1.7.0beta34 - March 17, 2014
+Makefiles for  libpng version 1.6.11beta02 - April 6, 2014

 pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng17.so.17.1.7.0beta34)
+                       (gcc, creates libpng16.so.16.1.6.11beta02)
 makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
 makefile.knr      =>  Archaic UNIX Makefile that converts files with
                       ansi2knr (Requires ansi2knr.c from
@@ -20,7 +20,7 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
 makefile.dec      =>  DEC Alpha UNIX makefile
 makefile.dj2      =>  DJGPP 2 makefile
 makefile.elf      =>  Linux/ELF makefile symbol versioning,
-                       (gcc, creates libpng17.so.17.1.7.0beta34)
+                       (gcc, creates libpng16.so.16.1.6.11beta02)
 makefile.freebsd  =>  FreeBSD makefile
 makefile.gcc      =>  Generic gcc makefile
 makefile.hpgcc    =>  HPUX makefile using gcc
@@ -35,12 +35,12 @@ 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 libpng17.so.17.1.7.0beta34)
+                       creates libpng16.so.16.1.6.11beta02)
 makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
 makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng17.so.17.1.7.0beta34)
+                       creates libpng16.so.16.1.6.11beta02)
 makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng17.so.17.1.7.0beta34)
+                       creates libpng16.so.16.1.6.11beta02)
 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 1.7.0beta34"
+PNG_DFN ";Version 1.6.11beta02"

 #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/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -11,7 +11,7 @@

 # Modeled after libxml-config.

-version=1.7.0beta34
+version=1.6.11beta02
 prefix=""
 libdir=""
 libs=""
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -1,10 +1,10 @@
 prefix=@prefix@
 exec_prefix=@exec_prefix@
 libdir=@libdir@
-includedir=@includedir@/libpng17
+includedir=@includedir@/libpng16

 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.7.0beta34
-Libs: -L${libdir} -lpng17
+Version: 1.6.11beta02
+Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}
--- a/scripts/makefile.32sunu
+++ b/scripts/makefile.32sunu
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -29,7 +29,7 @@ RM_F=/bin/rm -f
 SUN_CC_FLAGS=-fast -xtarget=ultra
 SUN_LD_FLAGS=-fast -xtarget=ultra

-# where make install puts libpng.a, libpng17.so and libpng17/png.h
+# where make install puts libpng.a, libpng16.so and libpng16/png.h
 prefix=/a
 exec_prefix=$(prefix)

@@ -98,7 +98,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -109,7 +109,7 @@ libpng-config:
 	echo R_opts=\"-R$(LIBPATH)\"; \
 	echo ccopts=\"-xtarget=ultra\"; \
 	echo ldopts=\"-xtarget=ultra\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.64sunu
+++ b/scripts/makefile.64sunu
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -29,7 +29,7 @@ RM_F=/bin/rm -f
 SUN_CC_FLAGS=-fast -xtarget=ultra -xarch=v9
 SUN_LD_FLAGS=-fast -xtarget=ultra -xarch=v9

-# where make install puts libpng.a, libpng17.so and libpng17/png.h
+# where make install puts libpng.a, libpng16.so and libpng16/png.h
 prefix=/a
 exec_prefix=$(prefix)

@@ -47,7 +47,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS= $(SUN_CC_FLAGS) # $(WARNMORE) -g
-LDFLAGS=-L. -R. $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -R. $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -98,7 +98,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -109,7 +109,7 @@ libpng-config:
 	echo R_opts=\"-R$(LIBPATH)\"; \
 	echo ccopts=\"-xtarget=ultra -xarch=v9\"; \
 	echo ldopts=\"-xtarget=ultra -xarch=v9\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.aix
+++ b/scripts/makefile.aix
@@ -21,8 +21,8 @@ RANLIB = ranlib
 RM_F = rm -f
 LN_SF = ln -f -s

-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 prefix=/usr/local
 INCPATH=$(prefix)/include
@@ -44,7 +44,7 @@ DL=$(DESTDIR)$(LIBPATH)
 WARNMORE =
 CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS = -W -Wall -O2 # $(WARNMORE) -g
-LDFLAGS = -L. -L$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS = -L. -L$(ZLIBLIB) -lpng16 -lz -lm

 # Variables
 OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
--- 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 scripts/pnglibconf.h.prebuilt TO pnglibconf.h

 pngtest: pngtest.o libpng.lib
 $(LN) <WITH <
--- a/scripts/makefile.atari
+++ b/scripts/makefile.atari
@@ -29,6 +29,10 @@ LIBPATH=$(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)\
@@ -44,8 +48,8 @@ $(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 $< $@

 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
@@ -49,6 +50,10 @@ 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
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 ## Variables
 OBJS = \
 	png.obj \
@@ -111,10 +116,8 @@ 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) $< $@

 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
--- a/scripts/makefile.beos
+++ b/scripts/makefile.beos
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -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
@@ -45,7 +46,7 @@ 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

-# where make install puts libpng.a, libpng17.so*, and png.h
+# where make install puts libpng.a, libpng16.so*, and png.h
 prefix=/usr/local
 exec_prefix=$(prefix)
 INCPATH=$(prefix)/include
@@ -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
@@ -81,9 +86,8 @@ OBJSDLL = $(OBJS)

 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -94,13 +98,13 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
 	echo prefix=\"$(prefix)\"; \
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo libs=\"-lpng17 -lz \"; \
+	echo libs=\"-lpng16 -lz \"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

@@ -113,7 +117,7 @@ $(LIBSOMAJ): $(OBJSDLL)
 	$(LIBSOMAJ) $(OBJSDLL) $(LDFLAGS)

 pngtest: pngtest.o $(LIBSO)
-	$(CC) -L$(ZLIBLIB) -L. -lz -lpng17 -o pngtest pngtest.o
+	$(CC) -L$(ZLIBLIB) -L. -lz -lpng16 -o pngtest pngtest.o

 test: pngtest
 	./pngtest
--- 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
@@ -57,6 +58,10 @@ 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
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 ## Variables

 OBJS = \
@@ -110,9 +115,9 @@ LIBNAME=libpng$(MODEL).lib

 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) $< $@

 libpng: $(LIBNAME)

--- a/scripts/makefile.cegcc
+++ b/scripts/makefile.cegcc
@@ -22,16 +22,16 @@
 # make clean

 VERMAJ = 1
-VERMIN = 7
-VERMIC = 0
+VERMIN = 6
+VERMIC = 11
 VER = $(VERMAJ).$(VERMIN).$(VERMIC)
 NAME = libpng
 PACKAGE = $(NAME)-$(VER)

-BIN = libpng17-0.dll
-LIB = libpng17.a libpng17.dll.a libpng.a libpng.dll.a
+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
-PC = libpng17.pc libpng.pc
+PC = libpng16.pc libpng.pc

 MANIFESTVERBIN = "Libpng-$(VER): Binary files"
 MANIFESTVERDEV = "Libpng-$(VER): Developer files"
--- a/scripts/makefile.darwin
+++ b/scripts/makefile.darwin
@@ -9,7 +9,7 @@
 # For conditions of distribution and use, see the disclaimer
 # and license in png.h

-# where "make install" puts libpng.a, libpng17.dylib, png.h, pngconf.h,
+# where "make install" puts libpng.a, libpng16.dylib, png.h, pngconf.h,
 # and pnglibconf.h
 prefix=/usr/local
 exec_prefix=$(prefix)
@@ -19,8 +19,8 @@ ZLIBLIB=/usr/lib
 ZLIBINC=/usr/include

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).dylib
@@ -34,13 +34,14 @@ 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

 CPPFLAGS=-I$(ZLIBINC)
 # CFLAGS=-W -Wall -O3 -funroll-loops
 CFLAGS=-W -Wall -O -funroll-loops $(ARCH)
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng17 -lz $(ARCH)
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz $(ARCH)

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -62,6 +63,10 @@ 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
@@ -78,9 +83,8 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -91,14 +95,14 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
 	echo prefix=\"$(prefix)\"; \
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz\"; \
+	echo libs=\"-lpng16 -lz\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

@@ -108,7 +112,7 @@ $(LIBSO): $(LIBSOMAJ)
 $(LIBSOMAJ): $(OBJSDLL)
 	$(CC) -dynamiclib \
 	 -install_name $(LIBPATH)/$(LIBSOMAJ) \
-	 -current_version 17 -compatibility_version 17 \
+	 -current_version 16 -compatibility_version 16 \
 	 $(ARCH) -o $(LIBSOMAJ) \
 	 $(OBJSDLL) -L$(ZLIBLIB) -lz

--- a/scripts/makefile.dec
+++ b/scripts/makefile.dec
@@ -7,8 +7,8 @@
 # and license in png.h

 # Library name:
-PNGMAJ = 17
-LIBNAME = libpng17
+PNGMAJ = 16
+LIBNAME = libpng16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -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
@@ -57,6 +58,10 @@ 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
@@ -66,9 +71,8 @@ OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@  $(OBJS)
@@ -79,7 +83,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -87,7 +91,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo ccopts=\"-std\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

@@ -181,7 +185,7 @@ test-installed:
 	./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

--- a/scripts/makefile.dj2
+++ b/scripts/makefile.dj2
@@ -19,6 +19,13 @@ 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
@@ -28,9 +35,8 @@ OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.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) $< $@

 libpng.a: $(OBJS)
 	ar rc $@  $(OBJS)
@@ -43,7 +49,7 @@ 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.

--- a/scripts/makefile.elf
+++ b/scripts/makefile.elf
@@ -1,4 +1,4 @@
-# makefile for libpng.a and libpng17.so on Linux ELF with gcc
+# makefile for libpng.a and libpng16.so on Linux ELF with gcc
 # Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2014 Greg Roelofs
 # and Glenn Randers-Pehrson
 # Copyright (C) 1996, 1997 Andreas Dilger
@@ -10,19 +10,19 @@
 # Modified for Debian by Junichi Uekawa and Josselin Mouette
 # Major modifications are:
 #    * link libpng explicitly with libz and libm
-#    * $(OLDSO).17 is a symlink rather than a different library
+#    * $(OLDSO).16 is a symlink rather than a different library
 #    * versioned symbols

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
 LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
 LIBSOREL=$(LIBSOMAJ).$(RELEASE)
 OLDSO=libpng.so
-OLDSOMAJ=libpng.so.17
+OLDSOMAJ=libpng.so.16

 # Utilities:
 AR_RC=ar rc
@@ -30,10 +30,11 @@ CC=gcc
 MKDIR_P=mkdir -p
 LN_SF=ln -sf
 RANLIB=ranlib
+CP=cp
 RM_F=/bin/rm -f

-# where "make install" puts libpng17.a, libpng17.so*,
-# libpng17/png.h, libpng17/pngconf.h, and libpng17/pnglibconf.h
+# 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)
@@ -57,7 +58,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 CPPFLAGS=-D_REENTRANT # -DPNG_DEBUG=5
 CFLAGS=-W -Wall -O2 $(ALIGN) # $(WARNMORE) -g

-LDFLAGS=-L. -lpng17
+LDFLAGS=-L. -lpng16
 LDFLAGS_A=libpng.a -lz -lm
 LIBADDFLAGS=-lz -lm

@@ -82,6 +83,10 @@ 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
@@ -98,9 +103,8 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 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 $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -111,11 +115,11 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng.syms: png.h pngconf.h pnglibconf.h
 	$(CC) $(CPPFLAGS) $(CFLAGS) -E -DPNG_BUILDSYMS -DPNG_INTERNAL png.h |\
-	awk -F '[\t [\\]();]' -v PNGMAJ=$(PNGMAJ) 'BEGIN{printf("PNG17_%s {global:\n",PNGMAJ)}\
+	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) ";";\
@@ -132,8 +136,8 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"\"; \
 	echo R_opts=\"\"; \
-	echo libs=\"-lpng17\"; \
-	echo all_libs=\"-lpng17 $(LIBADDFLAGS)\"; \
+	echo libs=\"-lpng16\"; \
+	echo all_libs=\"-lpng16 $(LIBADDFLAGS)\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.freebsd
+++ b/scripts/makefile.freebsd
@@ -7,13 +7,13 @@
 # and license in png.h

 PREFIX?=        /usr/local
-SHLIB_VER?=     17
+SHLIB_VER?=     16

 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}
@@ -39,6 +39,10 @@ DPADD+=		${LIBM} ${LIBZ}
 CPPFLAGS+=	-I. -I${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
@@ -55,9 +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 $< $@

 DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
 writelock:
--- a/scripts/makefile.gcc
+++ b/scripts/makefile.gcc
@@ -16,6 +16,7 @@ CC = gcc
 LD = $(CC)
 AR_RC = ar rcs
 RANLIB = ranlib
+CP = cp
 RM_F = rm -f

 WARNMORE = -Wwrite-strings -Wpointer-arith -Wshadow \
@@ -29,6 +30,10 @@ LIBS = -lz -lm
 # File extensions
 EXEEXT =

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 # Variables
 OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
 	pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
@@ -37,9 +42,8 @@ OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
 # Targets
 all: static

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $< $@

 .c.o:
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
--- a/scripts/makefile.hp64
+++ b/scripts/makefile.hp64
@@ -19,8 +19,8 @@ ZLIBINC=/opt/zlib/include
 #   SHAREDLIB=libz.sl

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).sl
@@ -34,6 +34,7 @@ CC=cc
 MKDIR_P=mkdir -p
 LN_SF=ln -sf
 RANLIB=ranlib
+CP=cp
 RM_F=/bin/rm -f

 CPPFLAGS=-I$(ZLIBINC) \
@@ -44,7 +45,7 @@ CCFLAGS=-O -Ae -Wl,+vnocompatwarnings +DD64 +Z

 LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm

-# where make install puts libpng.a, libpng17.sl, and png.h
+# where make install puts libpng.a, libpng16.sl, and png.h
 prefix=/opt/libpng
 exec_prefix=$(prefix)
 INCPATH=$(prefix)/include
@@ -67,6 +68,10 @@ 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
@@ -83,9 +88,8 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -96,7 +100,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -104,7 +108,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo ccopts=\"-Ae +DA1.1 +DS2.0\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.hpgcc
+++ b/scripts/makefile.hpgcc
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).sl
@@ -25,6 +25,7 @@ AR_RC=ar rc
 MKDIR_P=mkdir -p
 LN_SF=ln -sf
 RANLIB=ranlib
+CP=cp
 RM_F=/bin/rm -f

 # where "make install" puts libpng.a, $(OLDSO)*, png.h, pngconf.h
@@ -55,8 +56,8 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \

 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS=-W -Wall -O3 -funroll-loops $(ALIGN) # $(WARNMORE) -g
-#LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng17 -lz -lm
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng17 -lz -lm
+#LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng16 -lz -lm
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -103,13 +104,13 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
 	echo prefix=\"$(prefix)\"; \
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -20,8 +20,8 @@ ZLIBINC=/opt/zlib/include
 #   SHAREDLIB=libz.sl

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).sl
@@ -37,7 +37,7 @@ LN_SF=ln -sf
 RANLIB=ranlib
 RM_F=/bin/rm -f

-# where make install puts libpng.a, libpng17.sl, and png.h
+# where make install puts libpng.a, libpng16.sl, and png.h
 prefix=/opt/libpng
 exec_prefix=$(prefix)
 INCPATH=$(prefix)/include
@@ -66,6 +66,10 @@ 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
@@ -82,9 +86,8 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -95,7 +98,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -103,7 +106,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo ccopts=\"-Ae +DA1.1 +DS2.0\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.ibmc
+++ b/scripts/makefile.ibmc
@@ -21,12 +21,17 @@ ZLIBLIB = ../zlib
 CC = icc
 LD = ilink
 AR = ilib
+CP = copy
 RM = del

 CPPFLAGS = -I$(ZLIBINC)
 CFLAGS = -Mc -O2 -W3
 LDFLAGS =

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 # File extensions
 O=.obj
 A=.lib
@@ -45,9 +50,8 @@ LIBS = libpng$(A) $(ZLIBLIB)/zlib$(A)

 all: libpng$(A) pngtest$(E)

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $< $@

 libpng$(A): $(OBJS)
 	$(AR) -out:$@ $(OBJS)
--- a/scripts/makefile.intel
+++ b/scripts/makefile.intel
@@ -36,6 +36,11 @@ CPPFLAGS=-I$(ZLIBINC)
 CFLAGS=-O2 -G$(CPU)$(CALLING) -Qip -Qunroll4 -nologo
 LD=link
 LDFLAGS=/SUBSYSTEM:CONSOLE /NOLOGO
+CP=cp
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt

 O=.obj

@@ -45,9 +50,8 @@ pngrtran$(O) pngwtran$(O) pngrio$(O) pngwio$(O)

 all: test

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $< $@

 png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 	$(CC) $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
--- a/scripts/makefile.knr
+++ b/scripts/makefile.knr
@@ -36,15 +36,21 @@ ANSI2KNRFLAGS=
 RANLIB = ranlib
 #RANLIB = echo

+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

 all: ansi2knr 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) $< $@

 # general rule to allow ansi2knr to work
 .c.o:
@@ -83,7 +89,7 @@ install: libpng.a png.h pngconf.h pnglibconf.h
 	chmod 644 $(DESTDIR)$(LIBPATH)/libpng.a

 clean:
-	rm -f *.o libpng.a pngtest pngout.png ansi2knr pnglibconf.h
+	$(RM_F) *.o libpng.a pngtest pngout.png ansi2knr pnglibconf.h

 DOCS = ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO
 writelock:
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -1,4 +1,4 @@
-# makefile for libpng.a and libpng17.so on Linux ELF with gcc
+# makefile for libpng.a and libpng16.so on Linux ELF with gcc
 # Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2014 Greg Roelofs and
 # Glenn Randers-Pehrson
 # Copyright (C) 1996, 1997 Andreas Dilger
@@ -8,9 +8,9 @@
 # and license in png.h

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
-RELEASE = 0
+LIBNAME = libpng16
+PNGMAJ = 16
+RELEASE = 11

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -24,10 +24,11 @@ CC=gcc
 MKDIR_P=mkdir -p
 LN_SF=ln -sf
 RANLIB=ranlib
+CP=cp
 RM_F=/bin/rm -f

-# where "make install" puts libpng17.a, libpng17.so*,
-# libpng17/png.h, libpng17/pngconf.h, and libpng17/pnglibconf.h
+# 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=$(prefix)
@@ -52,7 +53,7 @@ CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS= -W -Wall -O3 -funroll-loops \
 	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5

-LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng16 -lz -lm
 LDFLAGS_A=-L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) libpng.a -lz -lm

 INCPATH=$(prefix)/include
@@ -75,6 +76,10 @@ DI=$(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
@@ -91,9 +96,8 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 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 $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -104,7 +108,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -112,7 +116,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-Wl,-rpath,$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.mips
+++ b/scripts/makefile.mips
@@ -30,6 +30,12 @@ LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
 #RANLIB=ranlib
 RANLIB=echo

+CP=cp
+
+# 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
@@ -39,9 +45,8 @@ OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.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) $< $@

 libpng.a: $(OBJS)
 	ar rc $@  $(OBJS)
--- a/scripts/makefile.msc
+++ b/scripts/makefile.msc
@@ -16,8 +16,13 @@ CFLAGS=-Oait -Gs -nologo -W3 -A$(MODEL)
 CC=cl
 LD=link
 LDFLAGS=/e/st:0x1500/noe
+CP=copy
 O=.obj

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 #uncomment next to put error messages in a file
 ERRFILE= >> pngerrs

@@ -28,12 +33,11 @@ OBJS3 = pngrtran$(O) pngwtran$(O) pngrio$(O) pngwio$(O)

 all: libpng.lib

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $< $@

 png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-		  $(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)

 pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
--- a/scripts/makefile.msys
+++ b/scripts/makefile.msys
@@ -16,9 +16,9 @@ prefix=/usr/local
 exec_prefix=$(prefix)

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
-RELEASE = 0
+LIBNAME = libpng16
+PNGMAJ = 16
+RELEASE = 11

 # Shared library names:
 LIBSO=$(LIBNAME).dll
@@ -37,6 +37,7 @@ CC = gcc
 LD = $(CC)
 AR_RC = ar rcs
 RANLIB = ranlib
+CP = cp
 RM_F = rm -rf
 MKDIR_P=mkdir -p
 LN_SF=ln -sf
@@ -73,6 +74,10 @@ DI=$(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
+
 # Variables
 OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
 	pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
@@ -81,9 +86,8 @@ OBJS =  png.o pngerror.o pngget.o pngmem.o pngpread.o \
 # Targets
 all: static shared

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $< $@

 .c.o:
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
@@ -122,7 +126,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -130,7 +134,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-Wl,-rpath,$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config

 install-shared: install-headers $(LIBSOMAJ) libpng.pc
--- a/scripts/makefile.ne12bsd
+++ b/scripts/makefile.ne12bsd
@@ -13,11 +13,11 @@
 LOCALBASE?=/usr/local
 LIBDIR=	${LOCALBASE}/lib
 MANDIR= ${LOCALBASE}/man
-INCSDIR=${LOCALBASE}/include/libpng17
+INCSDIR=${LOCALBASE}/include/libpng16

-LIB=	png17
+LIB=	png16
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.7.0beta34
+SHLIB_MINOR=	1.6.11beta02
 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
@@ -26,6 +26,10 @@ MAN=	libpng.3 libpngpf.3 png.5

 CPPFLAGS+=-I${.CURDIR}

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt
+
 # We should be able to do something like this instead of the manual
 # uncommenting, but it core dumps for me at the moment:
 # .if ${MACHINE_ARCH} == "i386"
@@ -37,9 +41,8 @@ CLEANFILES+=pngtest.o pngtest pnglibconf.h
 .c.o:
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	cp $< $@

 pngtest.o:	pngtest.c
 	${CC} -c ${CPPFLAGS} ${CFLAGS} ${.ALLSRC} -o ${.TARGET}
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -8,7 +8,7 @@
 # For conditions of distribution and use, see the disclaimer
 # and license in png.h

-# You should also run makefile.ne17bsd
+# You should also run makefile.ne16bsd

 LOCALBASE?=/usr/local
 LIBDIR=	${LOCALBASE}/lib
@@ -16,8 +16,8 @@ MANDIR= ${LOCALBASE}/man
 INCSDIR=${LOCALBASE}/include

 LIB=	png
-SHLIB_MAJOR=	17
-SHLIB_MINOR=	1.7.0beta34
+SHLIB_MAJOR=	16
+SHLIB_MINOR=	1.6.11beta02
 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
@@ -26,6 +26,10 @@ MAN=	libpng.3 libpngpf.3 png.5

 CPPFLAGS+=-I${.CURDIR}

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt
+
 # We should be able to do something like this instead of the manual
 # uncommenting, but it core dumps for me at the moment:
 # .if ${MACHINE_ARCH} == "i386"
@@ -37,9 +41,8 @@ CLEANFILES+=pngtest.o pngtest pnglibconf.h
 .c.o:
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	cp $< $@

 pngtest.o:	pngtest.c
 	${CC} -c ${CPPFLAGS} ${CFLAGS} ${.ALLSRC} -o ${.TARGET}
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -10,8 +10,8 @@ PREFIX?= /usr/local
 LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat

-SHLIB_MAJOR=	17
-SHLIB_MINOR=	1.7.0beta34
+SHLIB_MAJOR=	16
+SHLIB_MINOR=	1.6.11beta02

 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
@@ -31,12 +31,15 @@ MAN=	libpng.3 libpngpf.3 png.5
 DOCS=	ANNOUNCE CHANGES INSTALL KNOWNBUG LICENSE README TODO Y2KINFO \
 	libpng-manual.txt

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt
+
 .c.o:
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	cp $< $@

 pngtest.o:	pngtest.c
 	${CC} ${CPPFLAGS} ${CFLAGS} -c ${.ALLSRC} -o ${.TARGET}
--- a/scripts/makefile.sco
+++ b/scripts/makefile.sco
@@ -10,8 +10,8 @@
 # and license in png.h

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -25,6 +25,7 @@ AR_RC=ar rc
 MKDIR_P=mkdir
 LN_SF=ln -f -s
 RANLIB=echo
+CP=cp
 RM_F=/bin/rm -f

 # where make install puts libpng.a, $(OLDSO)*, and png.h
@@ -39,7 +40,7 @@ ZLIBINC=../zlib

 CPPFLAGS=-I$(ZLIBINC)
 CFLAGS= -dy -belf -O3
-LDFLAGS=-L. -L$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz -lm

 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
@@ -77,9 +82,8 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -90,7 +94,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -98,7 +102,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo ccopts=\"-belf\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.sggcc
+++ b/scripts/makefile.sggcc
@@ -1,4 +1,4 @@
-# makefile for libpng.a and libpng17.so, SGI IRIX with 'cc'
+# makefile for libpng.a and libpng16.so, SGI IRIX with 'cc'
 # Copyright (C) 2001-2002, 2006, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
 #
@@ -7,8 +7,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -22,9 +22,10 @@ CC=gcc
 MKDIR_P=mkdir -p
 LN_SF=ln -sf
 RANLIB=echo
+CP=cp
 RM_F=/bin/rm -f

-# Where make install puts libpng.a, libpng17.so, and libpng17/png.h
+# Where make install puts libpng.a, libpng16.so, and libpng16/png.h
 # Prefix must be a full pathname.

 prefix=/usr/local
@@ -71,6 +72,10 @@ 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
@@ -80,9 +85,8 @@ OBJS =  png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \

 all: libpng.a pngtest shared 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -95,7 +99,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -106,7 +110,7 @@ libpng-config:
 	echo ldopts=\"$(ABI)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo libdir=\"$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.sgi
+++ b/scripts/makefile.sgi
@@ -1,4 +1,4 @@
-# makefile for libpng.a and libpng17.so, SGI IRIX with 'cc'
+# makefile for libpng.a and libpng16.so, SGI IRIX with 'cc'
 # Copyright (C) 2001-2002, 2006, 2007, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
 #
@@ -7,8 +7,8 @@
 # and license in png.h

 # Library name:
-LIBNAME=libpng17
-PNGMAJ = 17
+LIBNAME=libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -22,9 +22,10 @@ CC=cc
 MKDIR_P=mkdir -p
 LN_SF=ln -sf
 RANLIB=echo
+CP=cp
 RM_F=/bin/rm -f

-# Where make install puts libpng.a, libpng17.so, and libpng17/png.h
+# Where make install puts libpng.a, libpng16.so, and libpng16/png.h
 # Prefix must be a full pathname.

 prefix=/usr/local
@@ -47,7 +48,7 @@ WARNMORE=-fullwarn
 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 #CFLAGS= $(ABI) -O $(WARNMORE) -KPIC # -g
 CFLAGS=$(ABI) -O $(WARNMORE)
-LDFLAGS_A=$(ABI) -L. -L$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS_A=$(ABI) -L. -L$(ZLIBLIB) -lpng16 -lz -lm
 LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm
 LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
 	-set_version sgi$(PNGMAJ).0
@@ -74,6 +75,10 @@ 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
@@ -83,9 +88,8 @@ OBJS =  png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \

 all: libpng.a pngtest shared 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -96,7 +100,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -106,7 +110,7 @@ libpng-config:
 	echo ldopts=\"$(ABI)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo libdir=\"$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.so9
+++ b/scripts/makefile.so9
@@ -10,8 +10,8 @@
 # and license in png.h

 # Library name:
-PNGMAJ = 17
-LIBNAME = libpng17
+PNGMAJ = 16
+LIBNAME = libpng16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -26,6 +26,7 @@ AR_RC=ar rc
 MKDIR_P=mkdir -p
 LN_SF=ln -f -s
 RANLIB=echo
+CP=cp
 RM_F=/bin/rm -f

 # Where make install puts libpng.a, $(OLDSO)*, and png.h
@@ -49,7 +50,7 @@ ZLIBINC=/usr/include
 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 #CFLAGS=-W -Wall -O3 $(WARNMORE) -g
 CFLAGS=-O3
-LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -71,6 +72,10 @@ 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
@@ -87,9 +92,8 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -100,7 +104,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -108,7 +112,7 @@ libpng-config:
 	echo I_opts=\"-I$(INCPATH)/$(LIBNAME)\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.solaris
+++ b/scripts/makefile.solaris
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -24,9 +24,10 @@ CC=gcc
 MKDIR_P=mkdir -p
 LN_SF=ln -f -s
 RANLIB=echo
+CP=cp
 RM_F=/bin/rm -f

-# Where make install puts libpng.a, libpng17.so*, and png.h
+# Where make install puts libpng.a, libpng16.so*, and png.h
 prefix=/usr/local
 exec_prefix=$(prefix)

@@ -45,7 +46,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS= -W -Wall -O \
 	# $(WARNMORE) -g -DPNG_DEBUG=5
-LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -67,6 +68,10 @@ 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
@@ -83,9 +88,8 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -96,7 +100,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -105,7 +109,7 @@ libpng-config:
 	echo cppflags=\"\"; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.solaris-x86
+++ b/scripts/makefile.solaris-x86
@@ -9,8 +9,8 @@
 # and license in png.h

 # Library name:
-LIBNAME = libpng17
-PNGMAJ = 17
+LIBNAME = libpng16
+PNGMAJ = 16

 # Shared library names:
 LIBSO=$(LIBNAME).so
@@ -24,9 +24,10 @@ CC=gcc
 MKDIR_P=mkdir -p
 LN_SF=ln -f -s
 RANLIB=echo
+CP=cp
 RM_F=/bin/rm -f

-# Where make install puts libpng.a, libpng17.so*, and png.h
+# Where make install puts libpng.a, libpng16.so*, and png.h
 prefix=/usr/local
 exec_prefix=$(prefix)

@@ -44,7 +45,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS=-W -Wall -O # $(WARNMORE) -g
-LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng17 -lz -lm
+LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm

 INCPATH=$(prefix)/include
 LIBPATH=$(exec_prefix)/lib
@@ -66,6 +67,10 @@ 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
@@ -82,9 +87,8 @@ OBJSDLL = $(OBJS:.o=.pic.o)

 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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@ $(OBJS)
@@ -95,7 +99,7 @@ libpng.pc:
 	-e s!@exec_prefix@!$(exec_prefix)! \
 	-e s!@libdir@!$(LIBPATH)! \
 	-e s!@includedir@!$(INCPATH)! \
-	-e s!-lpng17!-lpng17\ -lz\ -lm! > libpng.pc
+	-e s!-lpng16!-lpng16\ -lz\ -lm! > libpng.pc

 libpng-config:
 	( cat scripts/libpng-config-head.in; \
@@ -104,7 +108,7 @@ libpng-config:
 	echo cppflags=\""; \
 	echo L_opts=\"-L$(LIBPATH)\"; \
 	echo R_opts=\"-R$(LIBPATH)\"; \
-	echo libs=\"-lpng17 -lz -lm\"; \
+	echo libs=\"-lpng16 -lz -lm\"; \
 	cat scripts/libpng-config-body.in ) > libpng-config
 	chmod +x libpng-config

--- a/scripts/makefile.std
+++ b/scripts/makefile.std
@@ -32,6 +32,7 @@ AR_RC = ar rc
 MKDIR_P = mkdir
 LN_SF = ln -sf
 RANLIB = ranlib
+CP = cp
 RM_F = rm -f
 AWK = awk
 SED = sed
@@ -44,6 +45,10 @@ CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS = -O # -g
 LDFLAGS = -L. -L$(ZLIBLIB) -lpng -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
--- a/scripts/makefile.sunos
+++ b/scripts/makefile.sunos
@@ -37,12 +37,17 @@ AR_RC=ar rc
 MKDIR_P=mkdir -p
 LN_SF=ln -f -s
 RANLIB=ranlib
+CP=cp
 RM_F=/bin/rm -f

 CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
 CFLAGS=-O # $(WARNMORE)
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng -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
@@ -52,9 +57,8 @@ OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.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) $< $@

 libpng.a: $(OBJS)
 	$(AR_RC) $@  $(OBJS)
--- a/scripts/makefile.tc3
+++ b/scripts/makefile.tc3
@@ -12,6 +12,12 @@ CC=tcc
 LD=tcc
 LIB=tlib
 LDFLAGS=-m$(MODEL) -L..\zlib
+CP=copy
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 O=.obj
 E=.exe

@@ -25,9 +31,8 @@ OBJSL3 = +pngwrite$(O) +pngrtran$(O) +pngwtran$(O) +pngrio$(O) +pngwio$(O)

 all: libpng$(MODEL).lib pngtest$(E)

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	cp scripts/pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $< $@

 pngtest: pngtest$(E)

--- a/scripts/makefile.vcwin32
+++ b/scripts/makefile.vcwin32
@@ -9,9 +9,9 @@
 # Assumes that zlib.lib, zconf.h, and zlib.h have been copied to ..\zlib
 # To use, do "nmake /f scripts\makefile.vcwin32"

-# -------- Microsoft Visual C++ 2.0 and later, no assembler code --------
+# -------- Microsoft Visual C++ 2.0 and later --------

-# Compiler, linker, librarian, and other tools
+# Compiler, linker, librarian and other tools
 CC = cl
 LD = link
 AR = lib
@@ -19,8 +19,13 @@ CPPFLAGS = -I..\zlib
 CFLAGS  = -nologo -D_CRT_SECURE_NO_DEPRECATE -MD -O2 -W3
 LDFLAGS = -nologo
 ARFLAGS = -nologo
+CP = copy
 RM = del

+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
 # File extensions
 O=.obj

@@ -36,9 +41,8 @@ OBJS  = $(OBJS1) $(OBJS2) $(OBJS3)
 # Targets
 all: libpng.lib

-# see scripts/pnglibconf.mak for more options
-pnglibconf.h: scripts\pnglibconf.h.prebuilt
-       copy scripts\pnglibconf.h.prebuilt $@
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+       $(CP) $< $@

 png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -8,7 +8,7 @@ com pnglibconf.h - library build configuration
 com
 version
 com
-com Copyright (c) 1998-2013 Glenn Randers-Pehrson
+com Copyright (c) 1998-2012 Glenn Randers-Pehrson
 com
 com This code is released under the libpng license.
 com For conditions of distribution and use, see the disclaimer
@@ -114,13 +114,6 @@ file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H

 logunsupported = 1

-# The following allows the output from configure to modify the contents of
-# pnglibconf.h
-
-@#ifdef HAVE_CONFIG_H
-@#  include "config.h"
-@#endif
-
 # PNG_USER_CONFIG has to be defined on the compiler command line
 # to cause pngusr.h to be read while constructing pnglibconf.h
 #
@@ -196,25 +189,9 @@ setting API_RULE default 0

 setting PREFIX

-# This says that a prefix has been added to zlib API function names; at present
-# it is informational, the builder of zlib must ensure that zlib.h contains the
-# appropriate renames
+# Default to using the read macros

-setting ZLIB_PREFIX
-
-# This is used to select an alternative zlib header file - it must look pretty
-# much like the standard zlib.h, but this makes it easier to ensure the correct
-# header file is used.  Set it to the "" or <> quoted file name (a full file
-# name is acceptable).  Prior to 1.7.0 this used "zlib.h", so it would use a
-# zlib.h in the same directory as the libpng source, from 1.7.0 it defaults to
-# just searching the -I directories.  Prior to 1.6.0 the #include appeared in
-# the exported header files - so it was quite important to use "zlib.h" to
-# ensure that applications always got the zlib.h from the same directory as
-# png.h.
-
-setting ZLIB_HEADER default <zlib.h>
-# include the file too, so that the defaults below are known
-@#  include <zlib.h>
+setting DEFAULT_READ_MACROS default 1

 # Implementation specific control of the optimizations, enabled by those
 # hardware or software options that need it (typically when run-time choices
@@ -250,37 +227,26 @@ option ARM_NEON_CHECK disabled requires ALIGNED_MEMORY,
   sets ARM_NEON_OPT 1

 # These settings configure the default compression level (0-9) and 'strategy';
-# strategy is as defined by the implementors of zlib. It describes the input
+# strategy is as defined by the implementors of zlib, it describes the input
 # data and modifies the zlib parameters in an attempt to optimize the balance
 # between search and huffman encoding in the zlib algorithms.  The defaults are
 # the zlib.h defaults - the apparently recursive definition does not arise
 # because the name of the setting is prefixed by PNG_
 #
 # The TEXT values are the defaults when writing compressed text (all forms)
+#
+# Include the zlib header too, so that the defaults below are known
+@#  include <zlib.h>

 # The '@' here means to substitute the value when pnglibconf.h is built
-setting ZLIB_VERNUM default @ZLIB_VERNUM
 setting Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
-# TODO: why aren't these Z_RLE; zlib.h says that Z_RLE, specifically, is
-# appropriate for PNG images, maybe it doesn't exist in all versions?
 setting Z_DEFAULT_STRATEGY default @Z_FILTERED
 setting Z_DEFAULT_NOFILTER_STRATEGY default @Z_DEFAULT_STRATEGY
+setting ZLIB_VERNUM default @ZLIB_VERNUM

 setting TEXT_Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
 setting TEXT_Z_DEFAULT_STRATEGY default @Z_DEFAULT_STRATEGY

-# Define this to something that will stop, at least, the current thread; control
-# cannot proceed beyond the PNG_ABORT operation and compilation of pngerror.c is
-# likely to fail if the operation implemented does not clearly terminate the
-# thread or process.  The default implementation is the ANSI-C abort function,
-# but any manner of C code may be used.
-
-setting ABORT default { (abort()); }
-
-# Default to using the read macros
-
-setting DEFAULT_READ_MACROS default 1
-
 # The alternative is to call functions to read PNG values, if
 # the functions are turned *off* the read macros must always
 # be enabled, so turning this off will actually force the
@@ -375,28 +341,40 @@ option USER_MEM

 option IO_STATE

-# Libpng limits: limit the size of images and data on read.
+# This is only for PowerPC big-endian and 680x0 systems
+# some testing, not enabled by default.
+# NO LONGER USED
+
+#option READ_BIG_ENDIAN disabled
+
+# Allow users to control limits on what the READ code will
+# read:
+
+# Added at libpng-1.2.43; adds limit fields to png_struct,
+# allows some usages of these fields
+
+option USER_LIMITS
+
+# Added at libpng-1.2.6; adds setting APIs, allows additional
+# usage of this field (UTSL)
+
+option SET_USER_LIMITS requires USER_LIMITS
+
+# Feature added at libpng-1.4.0, this flag added at 1.4.1
+option SET_USER_LIMITS enables SET_CHUNK_CACHE_LIMIT
+# Feature added at libpng-1.4.1, this flag added at 1.4.1
+
+option SET_USER_LIMITS enables SET_CHUNK_MALLOC_LIMIT
+
+# Libpng limits.
 #
-# If this option is disabled all the limit checking code will be disabled:
-
-option USER_LIMITS requires READ
-
-# If the following settings are *not* set libpng will not limit the size of
+# If these settings are *not* set libpng will not limit the size of
 # images or the size of data in ancilliary chunks.  This does lead to
-# security issues if PNG files come from untrusted sources.  Settings have the
-# following interpretations:
-#
-# USER_WIDTH_MAX: maximum width of an image that will be read
-# USER_HEIGHT_MAX: maximum height
-# USER_CHUNK_MALLOC_MAX: maximum in-memory (decompressed) size of a single chunk
-# USER_CHUNK_CACHE_MAX: maximum number of chunks to be cached
-#
-# Only chunks that are variable in number are counted towards the
-# USER_CHUNK_CACHE_MAX limit
+# security issues if PNG files come from untrusted sources.
 setting USER_WIDTH_MAX
 setting USER_HEIGHT_MAX
-setting USER_CHUNK_MALLOC_MAX
 setting USER_CHUNK_CACHE_MAX
+setting USER_CHUNK_MALLOC_MAX

 # To default all these settings to values that are large but probably
 # safe turn the SAFE_LIMITS option on; this will cause the value in
@@ -405,10 +383,6 @@ setting USER_CHUNK_CACHE_MAX
 option SAFE_LIMITS enables USER_LIMITS disabled
 = SAFE_LIMITS SAFE_LIMITS

-# If this option is enabled APIs to set the above limits at run time are added;
-# without these the hardwired (compile time) limits will be used.
-option SET_USER_LIMITS requires USER_LIMITS
-
 # All of the following options relate to code capabilities for
 # processing image data before creating a PNG or after reading one.
 # You can remove these capabilities safely and still be PNG
@@ -600,8 +574,9 @@ option GAMMA disabled
 option COLORSPACE enables GAMMA disabled

 # When an ICC profile is read, or png_set, it will be checked for a match
-# against known sRGB profiles if the sRGB handling is enabled.  This
-# setting controls how much work is done during the check:
+# against known sRGB profiles if the sRGB handling is enabled.  The
+# PNG_sRGB_PROFILE_CHECKS setting controls how much work is done during the
+# check:
 #
 # 0: Just validate the profile MD5 signature if present, otherwise use
 #    the checks in option 1.
@@ -857,8 +832,8 @@ option INFO_IMAGE

 option CHECK_FOR_INVALID_INDEX enables READ_CHECK_FOR_INVALID_INDEX
 option CHECK_FOR_INVALID_INDEX enables WRITE_CHECK_FOR_INVALID_INDEX
-option READ_CHECK_FOR_INVALID_INDEX requires READ disabled
-option WRITE_CHECK_FOR_INVALID_INDEX requires WRITE disabled
+option READ_CHECK_FOR_INVALID_INDEX requires READ, CHECK_FOR_INVALID_INDEX
+option WRITE_CHECK_FOR_INVALID_INDEX requires WRITE, CHECK_FOR_INVALID_INDEX

 # added at libpng-1.5.15
 option GET_PALETTE_MAX enables READ_GET_PALETTE_MAX WRITE_GET_PALETTE_MAX
--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -1,8 +1,8 @@
-/* libpng 1.7.0beta34 STANDARD API DEFINITION */
+/* libpng 1.6.11beta02 STANDARD API DEFINITION */

 /* pnglibconf.h - library build configuration */

-/* Libpng version 1.7.0beta34 - March 17, 2014 */
+/* Libpng version 1.6.11beta02 - April 6, 2014 */

 /* Copyright (c) 1998-2013 Glenn Randers-Pehrson */

@@ -102,6 +102,8 @@
 #define PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
 #define PNG_SEQUENTIAL_READ_SUPPORTED
 #define PNG_SETJMP_SUPPORTED
+#define PNG_SET_CHUNK_CACHE_LIMIT_SUPPORTED
+#define PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
 #define PNG_SET_OPTION_SUPPORTED
 #define PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
 #define PNG_SET_USER_LIMITS_SUPPORTED
@@ -184,7 +186,6 @@
 #define PNG_zTXt_SUPPORTED
 /* end of options */
 /* settings */
-#define PNG_ABORT { (abort()); }
 #define PNG_API_RULE 0
 #define PNG_COST_SHIFT 3
 #define PNG_DEFAULT_READ_MACROS 1
@@ -198,9 +199,8 @@
 #define PNG_TEXT_Z_DEFAULT_COMPRESSION (-1)
 #define PNG_TEXT_Z_DEFAULT_STRATEGY 0
 #define PNG_WEIGHT_SHIFT 8
-#define PNG_ZLIB_VERNUM 0 /* unknown */
 #define PNG_ZBUF_SIZE 8192
-#define PNG_ZLIB_HEADER <zlib.h>
+#define PNG_ZLIB_VERNUM 0 /* unknown */
 #define PNG_Z_DEFAULT_COMPRESSION (-1)
 #define PNG_Z_DEFAULT_NOFILTER_STRATEGY 0
 #define PNG_Z_DEFAULT_STRATEGY 1
--- a/scripts/symbols.def
+++ b/scripts/symbols.def
@@ -1,4 +1,4 @@
-;Version 1.7.0beta34
+;Version 1.6.11beta02
 ;--------------------------------------------------------------
 ; LIBPNG symbol list as a Win32 DEF file
 ; Contains all the symbols that can be exported from libpng
@@ -15,6 +15,7 @@ EXPORTS
 png_set_compression_buffer_size @7
 png_set_longjmp_fn @8
 png_longjmp @9
+ png_reset_zstream @10
 png_create_read_struct_2 @11
 png_create_write_struct_2 @12
 png_write_sig @13
@@ -23,9 +24,11 @@ EXPORTS
 png_write_chunk_data @16
 png_write_chunk_end @17
 png_create_info_struct @18
+ png_info_init_3 @19
 png_write_info_before_PLTE @20
 png_write_info @21
 png_read_info @22
+ png_convert_to_rfc1123 @23
 png_convert_from_struct_tm @24
 png_convert_from_time_t @25
 png_set_expand @26
@@ -101,6 +104,9 @@ EXPORTS
 png_malloc_warn @96
 png_free @97
 png_free_data @98
+ png_data_freer @99
+ png_malloc_default @100
+ png_free_default @101
 png_error @102
 png_chunk_error @103
 png_err @104
--- a/scripts/symbols.dfn
+++ b/scripts/symbols.dfn
@@ -11,11 +11,17 @@

 /* NOTE: making 'symbols.chk' checks both that the exported
 * symbols in the library don't change and (implicitly) that
- * scripts/pnglibconf.h.prebuilt is as expected.  If scripts/pnglibconf.h.prebuilt
- * is remade using scripts/pnglibconf.dfa then this checks the
- * .dfa file too.
+ * scripts/pnglibconf.h.prebuilt is as expected.
+ * If scripts/pnglibconf.h.prebuilt is remade using
+ * scripts/pnglibconf.dfa then this checks the .dfa file too.
 */

+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+	PNG_DFN "@" name "@ @@" ordinal "@"
+#define PNG_REMOVED(ordinal, type, name, args, attributes)\
+	PNG_DFN "; @" name "@ @@" ordinal "@"
+#define PNG_EXPORT_LAST_ORDINAL(ordinal)\
+
 #define PNG_EXPORTA(ordinal, type, name, args, attributes)\
        PNG_DFN "@" name "@ @@" ordinal "@"
 #define PNG_REMOVED(ordinal, type, name, args, attributes)\