[master] Imported from libpng-1.6.18.tar

[master] Imported from libpng-1.6.17.tar
[master] Imported from libpng-1.6.16.tar
2025-07-10 18:04:09 +02:00 · 2015-07-22 22:41:05 -05:00 · 2015-03-26 08:11:22 -05:00 · 2015-01-15 12:47:40 -05:00 · 2014-11-20 10:23:30 -06:00 · 2014-10-22 19:33:27 -05:00
249 changed files with 45125 additions and 54746 deletions
--- a/94
+++ b/94
@@ -1,44 +1,90 @@
+Libpng 1.6.18 - July 23, 2015

-Libpng 1.5.10beta01 - February 21, 2012
-
-This is not intended to be a public release.  It will be replaced
-within a few weeks by a public version or by another test version.
+This is a public release of libpng, intended for use in production codes.

 Files available for download:

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

-   1.5.10beta01.tar.xz (LZMA-compressed, recommended)
-   1.5.10beta01.tar.gz
-   1.5.10beta01.tar.bz2
+   libpng-1.6.18.tar.xz (LZMA-compressed, recommended)
+   libpng-1.6.18.tar.gz

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

-   lp1510b01.7z  (LZMA-compressed, recommended)
-   lp1510b01.zip
+   lpng1618.7z  (LZMA-compressed, recommended)
+   lpng1618.zip

 Other information:

-   1.5.10beta01-README.txt
-   1.5.10beta01-LICENSE.txt
+   libpng-1.6.18-README.txt
+   libpng-1.6.18-LICENSE.txt
+   libpng-1.6.18-*.asc (armored detached GPG signatures)

-Changes since the last public release (1.5.9):
+Changes since the last public release (1.6.17):
+  Removed PNG_SET_CHUNK_[CACHE|MALLOC]_LIMIT_SUPPORTED macros.  They
+    have been combined with PNG_SET_USER_LIMITS_SUPPORTED (resolves
+    bug report by Andrew Church).
+  Fixed rgb_to_gray checks and added tRNS checks to pngvalid.c.  This
+    fixes some arithmetic errors that caused some tests to fail on
+    some 32-bit platforms (Bug reports by Peter Breitenlohner [i686]
+    and Petr Gajdos [i586]).
+  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
+    (Bug report by Viktor Szaka'ts).
+  Replaced "unexpected" with an integer (0xabadca11) in pngset.c
+    where a long was expected, to avoid a compiler warning when PNG_DEBUG > 1.
+  Added contrib/examples/simpleover.c, to demonstrate how to handle
+    alpha compositing of multiple images, using the "simplified API"
+    and an example PNG generation tool, contrib/examples/genpng.c
+    (John Bowler).
+  PNG_RELEASE_BUILD replaces tests where the code depended on the build base
+    type and can be defined on the command line, allowing testing in beta
+    builds (John Bowler).
+  Avoid Coverity issue 80858 (REVERSE NULL) in pngtest.c
+  Avoid a harmless potential integer overflow in png_XYZ_from_xy() (Bug
+    report from Christopher Ferris).
+  Backport filter selection code from libpng-1.7.0beta51, to combine
+    sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
+  Changed png_voidcast(), etc., to voidcast(), etc., in contrib/tools/pngfix.c
+    to avoid confusion with the libpng private macros.
+  Fixed old cut&paste bug in the weighted filter selection code in
+    pngwutil.c, introduced in libpng-0.95, March 1997.
+  Removed WRITE_WEIGHTED_FILTERED code, to save a few kbytes of the
+    compiled library size. It never worked properly and as far as we can
+    tell, no one uses it. The png_set_filter_heuristics() and
+    png_set_filter_heuristics_fixed() APIs are retained but deprecated
+    and do nothing.
+  Quieted some Coverity issues in pngfix.c, png-fix-itxt.c, pngvalid.c,
+    pngstest.c, and pngimage.c. Most seem harmless, but png-fix-itxt
+    would only work with iTXt chunks with length 255 or less.
+  Removed non-working progressive reader 'skip' function. This
+    function has apparently never been used. It was implemented
+    to support back-door modification of png_struct in libpng-1.4.x
+    but (because it does nothing and cannot do anything) was apparently
+    never tested (John Bowler).
+  Fixed cexcept.h in which GCC 5 now reports that one of the auto
+    variables in the Try macro needs to be volatile to prevent value
+    being lost over the setjmp (John Bowler).
+  Added #ifdef's to contrib/examples programs so people don't try
+    to compile them without the minimum required support enabled
+    (suggested by Flavio Medeiros).
+  Eliminated the final two Coverity defects (insecure temporary file
+    handling in contrib/libtests/pngstest.c; possible overflow of
+    unsigned char in contrib/tools/png-fix-itxt.c). To use the "secure"
+    file handling, define PNG_USE_MKSTEMP, otherwise "tmpfile()" will
+    be used.
+  Removed some unused WEIGHTED_FILTER macros from pngstruct.h
+  Replaced arbitrary use of 'extern' with #define PNG_LINKAGE_*.  To
+    preserve API compatibility, the new defines all default to "extern"
+    (requested by Jan Nijtmans).
+  Belatedly added Mans Rullgard and James Yu to the list of Contributing
+    Authors.

-Version 1.5.10beta01 [February 21, 2012]
-  Removed two useless #ifdef directives from pngread.c and one from pngrutil.c
-  Always put the CMAKE_LIBRARY in "lib" (removed special WIN32 case).
-  Removed empty vstudio/pngstest directory (Clifford Yapp).
-  Eliminated redundant png_push_read_tEXt|zTXt|iTXt|unknown code from
-    pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
-    now that png_ptr->buffer is inaccessible to applications, the special
-    handling is no longer useful.
-  Fixed bug with png_handle_hIST with odd chunk length (Frank Busse).
-
-Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe) or to glennrp at users.sourceforge.net
+to subscribe)
+or to glennrp at users.sourceforge.net

 Glenn R-P
--- a/1595
+++ b/1595
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 # CMakeLists.txt

-# Copyright (C) 2007-2011 Glenn Randers-Pehrson
+# Copyright (C) 2007-2015 Glenn Randers-Pehrson

 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -9,33 +9,14 @@
 cmake_minimum_required(VERSION 2.4.4)
 set(CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS true)

-if(UNIX AND NOT DEFINED CMAKE_BUILD_TYPE)
-  if(CMAKE_MAJOR_VERSION EQUAL 2 AND CMAKE_MINOR_VERSION EQUAL 4)
-    # workaround CMake 2.4.x bug
-    set(CMAKE_BUILD_TYPE "RelWithDebInfo" CACHE STRING
-        "Choose the type of build, options are:
-           None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used)
-           Debug
-           Release
-           RelWithDebInfo
-           MinSizeRel.")
-  else()
-    set(CMAKE_BUILD_TYPE "RelWithDebInfo" CACHE STRING
-        "Choose the type of build, options are:
-           None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used)
-           Debug
-           Release
-           RelWithDebInfo
-           MinSizeRel.")
-  endif()
-endif()
+set(CMAKE_CONFIGURATION_TYPES "Release;Debug;MinSizeRel;RelWithDebInfo")

 project(libpng C)
 enable_testing()

 set(PNGLIB_MAJOR 1)
-set(PNGLIB_MINOR 5)
-set(PNGLIB_RELEASE 10)
+set(PNGLIB_MINOR 6)
+set(PNGLIB_RELEASE 18)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})

@@ -49,8 +30,7 @@ if(NOT WIN32)
    PATHS /usr/lib /usr/local/lib
  )
  if(NOT M_LIBRARY)
-    message(STATUS
-      "math library 'libm' not found - floating point support disabled")
+    message(STATUS "math lib 'libm' not found; floating point support disabled")
  endif()
 else()
  # not needed on windows
@@ -58,22 +38,14 @@ else()
 endif()

 # COMMAND LINE OPTIONS
-if(DEFINED PNG_SHARED)
-  option(PNG_SHARED "Build shared lib" ${PNG_SHARED})
-else()
-  option(PNG_SHARED "Build shared lib" ON)
-endif()
-if(DEFINED PNG_STATIC)
-  option(PNG_STATIC "Build static lib" ${PNG_STATIC})
-else()
-  option(PNG_STATIC "Build static lib" ON)
-endif()
-
-option(PNG_TESTS  "Build libpng tests" YES)
+option(PNG_SHARED "Build shared lib" ON)
+option(PNG_STATIC "Build static lib" ON)
+option(PNG_TESTS  "Build libpng tests" ON)

 # Many more configuration options could be added here
-option(PNG_DEBUG         "Build with debug output" NO)
-option(PNGARG            "Disable ANSI-C prototypes" NO)
+option(PNG_FRAMEWORK "Build OS X framework" OFF)
+option(PNG_DEBUG     "Build with debug output" OFF)
+option(PNGARG        "Disable ANSI-C prototypes" OFF)

 # SET LIBNAME
 set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR})
@@ -123,10 +95,11 @@ set(pngtest_sources
 set(pngvalid_sources
  contrib/libtests/pngvalid.c
 )
+set(pngstest_sources
+  contrib/libtests/pngstest.c
+)
 # SOME NEEDED DEFINITIONS

-add_definitions(-DPNG_CONFIGURE_LIBPNG)
-
 if(MSVC)
  add_definitions(-D_CRT_SECURE_NO_DEPRECATE)
 endif(MSVC)
@@ -138,8 +111,11 @@ endif()
 # NOW BUILD OUR TARGET
 include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${ZLIB_INCLUDE_DIR})

+unset(PNG_LIB_TARGETS)
+
 if(PNG_SHARED)
  add_library(${PNG_LIB_NAME} SHARED ${libpng_sources})
+  set(PNG_LIB_TARGETS ${PNG_LIB_NAME})
  if(MSVC)
    # msvc does not append 'lib' - do it here to have consistent name
    set_target_properties(${PNG_LIB_NAME} PROPERTIES PREFIX "lib")
@@ -149,9 +125,10 @@ if(PNG_SHARED)
 endif()

 if(PNG_STATIC)
-# does not work without changing name
+  # does not work without changing name
  set(PNG_LIB_NAME_STATIC ${PNG_LIB_NAME}_static)
  add_library(${PNG_LIB_NAME_STATIC} STATIC ${libpng_sources})
+  list(APPEND PNG_LIB_TARGETS ${PNG_LIB_NAME_STATIC})
  if(MSVC)
    # msvc does not append 'lib' - do it here to have consistent name
    set_target_properties(${PNG_LIB_NAME_STATIC} PROPERTIES PREFIX "lib")
@@ -159,6 +136,29 @@ if(PNG_STATIC)
  target_link_libraries(${PNG_LIB_NAME_STATIC} ${ZLIB_LIBRARY} ${M_LIBRARY})
 endif()

+if(PNG_FRAMEWORK)
+  set(PNG_LIB_NAME_FRAMEWORK ${PNG_LIB_NAME}_framework)
+  add_library(${PNG_LIB_NAME_FRAMEWORK} SHARED ${libpng_sources})
+  list(APPEND PNG_LIB_TARGETS ${PNG_LIB_NAME_FRAMEWORK})
+  set_target_properties(${PNG_LIB_NAME_FRAMEWORK} PROPERTIES
+    FRAMEWORK TRUE
+    FRAMEWORK_VERSION ${PNGLIB_VERSION}
+    MACOSX_FRAMEWORK_SHORT_VERSION_STRING ${PNGLIB_MAJOR}.${PNGLIB_MINOR}
+    MACOSX_FRAMEWORK_BUNDLE_VERSION ${PNGLIB_VERSION}
+    MACOSX_FRAMEWORK_IDENTIFIER org.libpng.libpng
+    XCODE_ATTRIBUTE_INSTALL_PATH "@rpath"
+    PUBLIC_HEADER "${libpng_public_hdrs}"
+    OUTPUT_NAME png)
+  target_link_libraries(${PNG_LIB_NAME_FRAMEWORK} ${ZLIB_LIBRARY} ${M_LIBRARY})
+endif()
+
+if(NOT PNG_LIB_TARGETS)
+  message(SEND_ERROR
+    "No library variant selected to build. "
+    "Please enable at least one of the following options: "
+    " PNG_STATIC, PNG_SHARED, PNG_FRAMEWORK")
+endif()
+
 if(PNG_SHARED AND WIN32)
  set_target_properties(${PNG_LIB_NAME} PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
 endif()
@@ -172,6 +172,40 @@ if(PNG_TESTS AND PNG_SHARED)
  add_executable(pngvalid ${pngvalid_sources})
  target_link_libraries(pngvalid ${PNG_LIB_NAME})
  add_test(pngvalid ./pngvalid)
+  add_executable(pngstest ${pngstest_sources})
+  target_link_libraries(pngstest ${PNG_LIB_NAME})
+  add_test(pngstest ./pngstest
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g01.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g02.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g04.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g16.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn2c08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn2c16.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn3p01.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn3p02.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn3p04.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn3p08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn4a08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn4a16.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn6a08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn6a16.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn0g01.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn0g02.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn0g04.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn2c16.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn3p08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbgn2c16.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbgn3p08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbrn2c08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbwn0g16.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbwn3p08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbyn3p08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftp0n0g08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftp0n2c08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftp0n3p08.png
+    ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftp1n3p08.png
+  )
 endif()

 # Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set
@@ -184,18 +218,20 @@ ENDIF(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
 # copies if different.
 macro(CREATE_SYMLINK SRC_FILE DEST_FILE)
  FILE(REMOVE ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
-  if(WIN32 AND NOT CYGWIN AND NOT MINGW)
+  if(WIN32 AND NOT CYGWIN AND NOT MSYS)
    ADD_CUSTOM_COMMAND(
        OUTPUT ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}   ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
-        COMMAND ${CMAKE_COMMAND} -E copy        ${CMAKE_CURRENT_BINARY_DIR}/${SRC_FILE} ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}
-        COMMAND ${CMAKE_COMMAND} -E copy        ${CMAKE_CURRENT_BINARY_DIR}/${SRC_FILE} ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
-        DEPENDS ${PNG_LIB_NAME} ${PNG_LIB_NAME_STATIC}
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different  "${SRC_FILE}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different  "${SRC_FILE}" ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
+        DEPENDS ${PNG_LIB_TARGETS}
        )
    ADD_CUSTOM_TARGET(${DEST_FILE}_COPY ALL DEPENDS ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
-  else(WIN32 AND NOT CYGWIN AND NOT MINGW)
-    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink ${SRC_FILE} ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
-    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink ${SRC_FILE} ${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
-  endif(WIN32 AND NOT CYGWIN AND NOT MINGW)
+  else(WIN32 AND NOT CYGWIN AND NOT MSYS)
+    get_filename_component(LINK_TARGET "${SRC_FILE}" NAME)
+    execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_LIBRARY_OUTPUT_DIRECTORY})
+    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
+    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
+  endif(WIN32 AND NOT CYGWIN AND NOT MSYS)
 endmacro()

 # libpng is a library so default to 'lib'
@@ -207,7 +243,7 @@ endif(NOT DEFINED CMAKE_INSTALL_LIBDIR)
 # we use the same files like ./configure, so we have to set its vars
 # Only do this on Windows for Cygwin - the files don't make much sense outside
 # a UNIX look alike
-if(NOT WIN32 OR CYGWIN OR MINGW) 
+if(NOT WIN32 OR CYGWIN OR MINGW)
  set(prefix      ${CMAKE_INSTALL_PREFIX})
  set(exec_prefix ${CMAKE_INSTALL_PREFIX})
  set(libdir      ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR})
@@ -225,9 +261,9 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
  set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#   VERSION 15.${PNGLIB_RELEASE}.1.5.10beta01
-    VERSION 15.${PNGLIB_RELEASE}.0
-    SOVERSION 15
+#   VERSION 16.${PNGLIB_RELEASE}.1.6.18
+    VERSION 16.${PNGLIB_RELEASE}.0
+    SOVERSION 16
    CLEAN_DIRECT_OUTPUT 1)
 endif()
 if(PNG_STATIC)
@@ -252,40 +288,34 @@ endif()

 # INSTALL
 if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
-  if(PNG_SHARED)
-    install(TARGETS ${PNG_LIB_NAME}
-        ${PNG_EXPORT_RULE}
-        RUNTIME DESTINATION bin
-        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
+  install(TARGETS ${PNG_LIB_TARGETS}
+      ${PNG_EXPORT_RULE}
+      RUNTIME DESTINATION bin
+      LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+      FRAMEWORK DESTINATION ${CMAKE_INSTALL_LIBDIR})

-    # Create a symlink for libpng.dll.a => libpng15.dll.a on Cygwin
+  if(PNG_SHARED)
+    # 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})
-       get_filename_component(BUILD_TARGET_FILE ${BUILD_TARGET_LOCATION} NAME)
-       CREATE_SYMLINK(${BUILD_TARGET_FILE} libpng${CMAKE_IMPORT_LIBRARY_SUFFIX})
+       CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_IMPORT_LIBRARY_SUFFIX})
       install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_IMPORT_LIBRARY_SUFFIX}
         DESTINATION ${CMAKE_INSTALL_LIBDIR})
    endif(CYGWIN OR MINGW)

    if(NOT WIN32)
      get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME} LOCATION_${CMAKE_BUILD_TYPE})
-      get_filename_component(BUILD_TARGET_FILE ${BUILD_TARGET_LOCATION} NAME)
-      CREATE_SYMLINK(${BUILD_TARGET_FILE} libpng${CMAKE_SHARED_LIBRARY_SUFFIX})
+      CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_SHARED_LIBRARY_SUFFIX})
      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
         DESTINATION ${CMAKE_INSTALL_LIBDIR})
    endif(NOT WIN32)
  endif(PNG_SHARED)

  if(PNG_STATIC)
-    install(TARGETS ${PNG_LIB_NAME_STATIC}
-        ${PNG_EXPORT_RULE}
-        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
    if(NOT WIN32 OR CYGWIN OR MINGW)
      get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME_STATIC} LOCATION_${CMAKE_BUILD_TYPE})
-      get_filename_component(BUILD_TARGET_FILE ${BUILD_TARGET_LOCATION} NAME)
-      CREATE_SYMLINK(${BUILD_TARGET_FILE} libpng${CMAKE_STATIC_LIBRARY_SUFFIX})
+      CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_STATIC_LIBRARY_SUFFIX})
      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
         DESTINATION ${CMAKE_INSTALL_LIBDIR})
    endif(NOT WIN32 OR CYGWIN OR MINGW)
@@ -330,7 +360,7 @@ if(PNG_EXPORT_RULE AND NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL )
  install(EXPORT libpng DESTINATION lib/libpng FILE lib${PNG_LIB_NAME}.cmake)
 endif()

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

 # UNINSTALL
 # do we need this?
--- a/316
+++ b/316
@@ -1,32 +1,69 @@

 Installing libpng

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

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

-and ignore the rest of this document.
+and ignore the rest of this document.  "/path" is the path to the directory
+where you want to install the libpng "lib", "include", and "bin"
+subdirectories.

-If configure does not work on your system and you have a reasonably
-up-to-date set of tools, running ./autogen.sh before running ./configure
-may fix the problem.  You can also run the individual commands in
-autogen.sh with the --force option, if supported by your version of
-the tools.  To be really sure that you aren't using any of the included
-pre-built scripts, you can do this:
+If you downloaded a GIT clone, you will need to run ./autogen.sh before
+running ./configure, to create "configure" and "Makefile.in" which are
+not included in the GIT repository.
+
+Note that "configure" is only included in the "*.tar" distributions and not
+in the "*.zip" or "*.7z" distributions. If you downloaded one of those
+distributions, see "Building with project files" or "Building with makefiles",
+below.
+
+II. Rebuilding the configure scripts
+
+If configure does not work on your system, or if you have a need to
+change configure.ac or Makefile.am, and you have a reasonably
+up-to-date set of tools, running ./autogen.sh in a git clone before
+running ./configure may fix the problem.  To be really sure that you
+aren't using any of the included pre-built scripts, you can do this:

    ./configure --enable-maintainer-mode
    make maintainer-clean
-    ./autogen.sh
+    ./autogen.sh --maintainer --clean
+    ./autogen.sh --maintainer
    ./configure [--prefix=/path] [other options]
    make
    make install
    make check

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

+    cp scripts/pnglibconf.h.prebuilt pnglibconf.h
    cp scripts/makefile.system makefile
    make test
    make install
@@ -38,8 +75,28 @@ Or you can use one of the "projects" in the "projects" directory.

 Before installing libpng, you must first install zlib, if it
 is not already on your system.  zlib can usually be found
-wherever you got libpng.  zlib can be placed in another directory,
-at the same level as libpng.
+wherever you got libpng; otherwise go to http://zlib.net.  You can place
+zlib in in the same directory as libpng or in another directory.
+
+If your system already has a preinstalled zlib you will still need
+to have access to the zlib.h and zconf.h include files that
+correspond to the version of zlib that's installed.
+
+If you wish to test with a particular zlib that is not first in the
+standard library search path, put ZLIBLIB, ZLIBINC, CPPFLAGS, LDFLAGS,
+and LD_LIBRARY_PATH in your environment before running "make test"
+or "make distcheck":
+
+ZLIBLIB=/path/to/lib export ZLIBLIB
+ZLIBINC=/path/to/include export ZLIBINC
+CPPFLAGS="-I$ZLIBINC" export CPPFLAGS
+LDFLAGS="-L$ZLIBLIB" export LDFLAGS
+LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
+
+If you are using one of the makefile scripts, put ZLIBLIB and ZLIBINC
+in your environment and type "make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test".
+
+IV. Using cmake

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

@@ -47,13 +104,15 @@ If you want to use "cmake" (see www.cmake.org), type
   make
   make install

-If your system already has a preinstalled zlib you will still need
-to have access to the zlib.h and zconf.h include files that
-correspond to the version of zlib that's installed.
+As when using the simple configure method described above, "/path" points to
+the installation directory where you want to put the libpng "lib", "include",
+and "bin" subdirectories.
+
+V. Directory structure

 You can rename the directories that you downloaded (they
-might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.5"
-or "zlib125") so that you have directories called "zlib" and "libpng".
+might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.8"
+or "zlib128") so that you have directories called "zlib" and "libpng".

 Your directory structure should look like this:

@@ -61,8 +120,7 @@ Your directory structure should look like this:
      libpng  (this directory)
          INSTALL (this file)
          README
-          *.h
-          *.c
+          *.h, *.c  => libpng source files
          CMakeLists.txt    =>  "cmake" script
          configuration files:
             configure.ac, configure, Makefile.am, Makefile.in,
@@ -70,14 +128,10 @@ Your directory structure should look like this:
             libpng-config.in, aclocal.m4, config.h.in, config.sub,
             depcomp, install-sh, mkinstalldirs, test-pngtest.sh
          contrib
-             gregbook
-             pngminim
-             pngminus
-             pngsuite
-             visupng
+             arm-neon, conftest, examples, gregbook, libtests, pngminim,
+             pngminus, pngsuite, tools, visupng
          projects
-             visualc71
-             vstudio
+             cbuilder5, owatcom, visualc71, vstudio, xcode
          scripts
             makefile.*
             *.def (module definition files)
@@ -85,29 +139,31 @@ Your directory structure should look like this:
          pngtest.png
          etc.
      zlib
-          README
-          *.h
-          *.c
-          contrib
-          etc.
+          README, *.h, *.c contrib, etc.

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

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

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

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

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

 Read the makefile to see if you need to change any source or
 target directories to match your preferences.
@@ -130,6 +186,202 @@ do that, run "make install" in the zlib directory first if necessary).
 Some also allow you to run "make test-installed" after you have
 run "make install".

+VIII. Configuring libpng for 16-bit platforms
+
+You will want to look into zconf.h to tell zlib (and thus libpng) that
+it cannot allocate more than 64K at a time.  Even if you can, the memory
+won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.
+
+IX. Configuring for DOS
+
+For DOS users who only have access to the lower 640K, you will
+have to limit zlib's memory usage via a png_set_compression_mem_level()
+call.  See zlib.h or zconf.h in the zlib library for more information.
+
+X. Configuring for Medium Model
+
+Libpng's support for medium model has been tested on most of the popular
+compilers.  Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
+defined, and FAR gets defined to far in pngconf.h, and you should be
+all set.  Everything in the library (except for zlib's structure) is
+expecting far data.  You must use the typedefs with the p or pp on
+the end for pointers (or at least look at them and be careful).  Make
+note that the rows of data are defined as png_bytepp, which is
+an "unsigned char far * far *".
+
+XI. Prepending a prefix to exported symbols
+
+Starting with libpng-1.6.0, you can configure libpng (when using the
+"configure" script) to prefix all exported symbols by means of the
+configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any
+string beginning with a letter and containing only uppercase
+and lowercase letters, digits, and the underscore (i.e., a C language
+identifier).  This creates a set of macros in pnglibconf.h, so this is
+transparent to applications; their function calls get transformed by
+the macros to use the modified names.
+
+XII. Configuring for compiler xxx:
+
+All includes for libpng are in pngconf.h.  If you need to add, change
+or delete an include, this is the place to do it.
+The includes that are not needed outside libpng are placed in pngpriv.h,
+which is only used by the routines inside libpng itself.
+The files in libpng proper only include pngpriv.h and png.h, which
+in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
+As of libpng-1.5.0, pngpriv.h also includes three other private header
+files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
+that previously appeared in the public headers.
+
+XIII. Removing unwanted object code
+
+There are a bunch of #define's in pngconf.h that control what parts of
+libpng are compiled.  All the defines end in _SUPPORTED.  If you are
+never going to use a capability, you can change the #define to #undef
+before recompiling libpng and save yourself code and data space, or
+you can turn off individual capabilities with defines that begin with
+PNG_NO_.
+
+In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
+
+You can also turn all of the transforms and ancillary chunk capabilities
+off en masse with compiler directives that define
+PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
+or all four, along with directives to turn on any of the capabilities that
+you do want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the
+extra transformations but still leave the library fully capable of reading
+and writing PNG files with all known public chunks. Use of the
+PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
+that is incapable of reading or writing ancillary chunks.  If you are
+not using the progressive reading capability, you can turn that off
+with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
+capability, which you'll still have).
+
+All the reading and writing specific code are in separate files, so the
+linker should only grab the files it needs.  However, if you want to
+make sure, or if you are building a stand alone library, all the
+reading files start with "pngr" and all the writing files start with "pngw".
+The files that don't match either (like png.c, pngtrans.c, etc.)
+are used for both reading and writing, and always need to be included.
+The progressive reader is in pngpread.c
+
+If you are creating or distributing a dynamically linked library (a .so
+or DLL file), you should not remove or disable any parts of the library,
+as this will cause applications linked with different versions of the
+library to fail if they call functions not available in your library.
+The size of the library itself should not be an issue, because only
+those sections that are actually used will be loaded into memory.
+
+XIV. Changes to the build and configuration of libpng in libpng-1.5.x
+
+Details of internal changes to the library code can be found in the CHANGES
+file and in the GIT repository logs.  These will be of no concern to the vast
+majority of library users or builders; however, the few who configure libpng
+to a non-default feature set may need to change how this is done.
+
+There should be no need for library builders to alter build scripts if
+these use the distributed build support - configure or the makefiles -
+however, users of the makefiles may care to update their build scripts
+to build pnglibconf.h where the corresponding makefile does not do so.
+
+Building libpng with a non-default configuration has changed completely.
+The old method using pngusr.h should still work correctly even though the
+way pngusr.h is used in the build has been changed; however, library
+builders will probably want to examine the changes to take advantage of
+new capabilities and to simplify their build system.
+
+A. Specific changes to library configuration capabilities
+
+The exact mechanism used to control attributes of API functions has
+changed.  A single set of operating system independent macro definitions
+is used and operating system specific directives are defined in
+pnglibconf.h
+
+As part of this the mechanism used to choose procedure call standards on
+those systems that allow a choice has been changed.  At present this only
+affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
+running on Intel processors.  As before, PNGAPI is defined where required
+to control the exported API functions; however, two new macros, PNGCBAPI
+and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
+(PNGCAPI) for functions that must match a C library prototype (currently
+only png_longjmp_ptr, which must match the C longjmp function.)  The new
+approach is documented in pngconf.h
+
+Despite these changes, libpng 1.5.0 only supports the native C function
+calling standard on those platforms tested so far (__cdecl on Microsoft
+Windows).  This is because the support requirements for alternative
+calling conventions seem to no longer exist.  Developers who find it
+necessary to set PNG_API_RULE to 1 should advise the mailing list
+(png-mng-implement) of this and library builders who use Openwatcom and
+therefore set PNG_API_RULE to 2 should also contact the mailing list.
+
+B. Changes to the configuration mechanism
+
+Prior to libpng-1.5.0 library builders who needed to configure libpng
+had either to modify the exported pngconf.h header file to add system
+specific configuration or had to write feature selection macros into
+pngusr.h and cause this to be included into pngconf.h by defining
+PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
+application built without PNG_USER_CONFIG defined would see the
+unmodified, default, libpng API and thus would probably fail to link.
+
+These mechanisms still work in the configure build and in any makefile
+build that builds pnglibconf.h, although the feature selection macros
+have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
+processed only once, at the time the exported header file pnglibconf.h is
+built.  pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
+after the build of pnglibconf.h and it is never included in an application
+build.
+
+The formerly used alternative of adding a list of feature macros to the
+CPPFLAGS setting in the build also still works; however, the macros will be
+copied to pnglibconf.h and this may produce macro redefinition warnings
+when the individual C files are compiled.
+
+All configuration now only works if pnglibconf.h is built from
+scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
+(the original author of awk) maintains C source code of that awk and this
+and all known later implementations (often called by subtly different
+names - nawk and gawk for example) are adequate to build pnglibconf.h.
+The Sun Microsystems (now Oracle) program 'awk' is an earlier version
+and does not work; this may also apply to other systems that have a
+functioning awk called 'nawk'.
+
+Configuration options are now documented in scripts/pnglibconf.dfa.  This
+file also includes dependency information that ensures a configuration is
+consistent; that is, if a feature is switched off, dependent features are
+also switched off.  As a recommended alternative to using feature macros in
+pngusr.h a system builder may also define equivalent options in pngusr.dfa
+(or, indeed, any file) and add that to the configuration by setting
+DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
+how to do this, and also illustrate a case where pngusr.h is still required.
+
+After you have built libpng, the definitions that were recorded in
+pnglibconf.h are available to your application (pnglibconf.h is included
+in png.h and gets installed alongside png.h and pngconf.h in your
+$PREFIX/include directory).  Do not edit pnglibconf.h after you have built
+libpng, because than the settings would not accurately reflect the settings
+that were used to build libpng.
+
+XV. Setjmp/longjmp issues
+
+Libpng uses setjmp()/longjmp() for error handling.  Unfortunately setjmp()
+is known to be not thread-safe on some platforms and we don't know of
+any platform where it is guaranteed to be thread-safe.  Therefore, if
+your application is going to be using multiple threads, you should
+configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with
+-DPNG_NO_SETJMP on your compile line, or with
+
+  #undef PNG_SETJMP_SUPPORTED
+
+in your pnglibconf.h or pngusr.h.
+
+Starting with libpng-1.6.0, the library included a "simplified API".
+This requires setjmp/longjmp, so you must either build the library
+with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
+and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
+
+XVI. Other sources of information about libpng:
+
 Further information can be found in the README and libpng-manual.txt
 files, in the individual makefiles, in png.h, and the manual pages
 libpng.3 and png.5.
@@ -147,7 +399,7 @@ CFLAGS="-Wall -O -funroll-loops \
 --with-pkgconfigdir=/usr/lib/pkgconfig --includedir=/usr/include

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

 If you find that the configure script is out-of-date or is not supporting
 your platform properly, try running autogen.sh to regenerate "configure",
--- a/48
+++ b/48
@@ -10,21 +10,17 @@ this sentence.

 This code is released under the libpng license.

-libpng versions 1.2.6, August 15, 2004, through 1.5.10beta01, February 19, 2012, are
-Copyright (c) 2004, 2006-2011 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
-
-   Cosmin Truta
-
-libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
-Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
+libpng versions 1.0.7, July 1, 2000, through 1.6.18, July 23, 2015, are
+Copyright (c) 2000-2002, 2004, 2006-2015 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.0.6
-with the following individuals added to the list of Contributing Authors
+with the following individuals added to the list of Contributing Authors:

   Simon-Pierre Cadieux
   Eric S. Raymond
+   Mans Rullgard
+   Cosmin Truta
   Gilles Vollant
+   James Yu

 and with the following additions to the disclaimer:

@@ -36,17 +32,17 @@ and with the following additions to the disclaimer:
   the user.

 libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
-Copyright (c) 1998, 1999 Glenn Randers-Pehrson, and are
-distributed according to the same disclaimer and license as libpng-0.96,
-with the following individuals added to the list of Contributing Authors:
+Copyright (c) 1998-2000 Glenn Randers-Pehrson, and are distributed according
+to the same disclaimer and license as libpng-0.96, with the following
+individuals added to the list of Contributing Authors:

   Tom Lane
   Glenn Randers-Pehrson
   Willem van Schaik

 libpng versions 0.89, June 1996, through 0.96, May 1997, are
-Copyright (c) 1996, 1997 Andreas Dilger
-Distributed according to the same disclaimer and license as libpng-0.88,
+Copyright (c) 1996-1997 Andreas Dilger, and are
+distributed according to the same disclaimer and license as libpng-0.88,
 with the following individuals added to the list of Contributing Authors:

   John Bowler
@@ -57,7 +53,7 @@ with the following individuals added to the list of Contributing Authors:
   Tom Tanner

 libpng versions 0.5, May 1995, through 0.88, January 1996, are
-Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.

 For the purposes of this copyright and license, "Contributing Authors"
 is defined as the following set of individuals:
@@ -80,13 +76,13 @@ Permission is hereby granted to use, copy, modify, and distribute this
 source code, or portions hereof, for any purpose, without fee, subject
 to the following restrictions:

-1. The origin of this source code must not be misrepresented.
+  1. The origin of this source code must not be misrepresented.

-2. Altered versions must be plainly marked as such and must not
-   be misrepresented as being the original source.
+  2. Altered versions must be plainly marked as such and must not
+     be misrepresented as being the original source.

-3. This Copyright notice may not be removed or altered from any
-   source or altered source distribution.
+  3. This Copyright notice may not be removed or altered from any
+     source or altered source distribution.

 The Contributing Authors and Group 42, Inc. specifically permit, without
 fee, and encourage the use of this source code as a component to
@@ -94,18 +90,18 @@ supporting the PNG file format in commercial products.  If you use this
 source code in a product, acknowledgment is not required but would be
 appreciated.

-
 A "png_get_copyright" function is available, for convenient use in "about"
 boxes and the like:

-   printf("%s",png_get_copyright(NULL));
+   printf("%s", png_get_copyright(NULL));

 Also, the PNG logo (in PNG format, of course) is supplied in the
 files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).

-Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is a
-certification mark of the Open Source Initiative.
+Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is
+a certification mark of the Open Source Initiative. OSI has not addressed
+the additional disclaimers inserted at version 1.0.7.

 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-February 19, 2012
+July 23, 2015
--- a/Makefile.am
+++ b/Makefile.am
@@ -4,25 +4,69 @@

 PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@

-# libpng does not follow GNU file name conventions
-
-# "color-tests" requires automake 1.11.1 or later.  Enable it if you like,
-# to get red "FAIL" and green "PASS" notations during tests.
-# AUTOMAKE_OPTIONS = foreign color-tests
-AUTOMAKE_OPTIONS = foreign
+ACLOCAL_AMFLAGS = -I scripts

 # test programs - run on make check, make distcheck
-TESTS_ENVIRONMENT= srcdir=$(srcdir)
-check_PROGRAMS= pngtest
+check_PROGRAMS= pngtest pngunknown pngstest pngvalid pngimage
+
+# Utilities - installed
+bin_PROGRAMS= pngfix png-fix-itxt
+
+# This ensures that pnglibconf.h gets built at the start of 'make all' or
+# 'make check', but it does not add dependencies to the individual programs,
+# this is done below.
+#
+# IMPORTANT: always add the object modules of new programs to the list below
+# because otherwise the sequence 'configure; make new-program' will *sometimes*
+# result in the installed (system) pnglibconf.h being used and the result is
+# always wrong and always very confusing.
+BUILT_SOURCES = pnglibconf.h
+
 pngtest_SOURCES = pngtest.c
 pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-TESTS = test-pngtest.sh

-# Only do the following if the contrib directory is present.
-check_PROGRAMS+= pngvalid
 pngvalid_SOURCES = contrib/libtests/pngvalid.c
 pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-TESTS += test-pngvalid-simple.sh test-pngvalid-full.sh
+
+pngstest_SOURCES = contrib/libtests/pngstest.c
+pngstest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngunknown_SOURCES = contrib/libtests/pngunknown.c
+pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngimage_SOURCES = contrib/libtests/pngimage.c
+pngimage_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngfix_SOURCES = contrib/tools/pngfix.c
+pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c
+
+# Generally these are single line shell scripts to run a test with a particular
+# set of parameters:
+TESTS =\
+   tests/pngtest\
+   tests/pngvalid-gamma-16-to-8 tests/pngvalid-gamma-alpha-mode\
+   tests/pngvalid-gamma-background tests/pngvalid-gamma-expand16-alpha-mode\
+   tests/pngvalid-gamma-expand16-background\
+   tests/pngvalid-gamma-expand16-transform tests/pngvalid-gamma-sbit\
+   tests/pngvalid-gamma-threshold tests/pngvalid-gamma-transform\
+   tests/pngvalid-progressive-interlace-size\
+   tests/pngvalid-progressive-interlace-standard\
+   tests/pngvalid-progressive-interlace-transform\
+   tests/pngvalid-progressive-standard tests/pngvalid-standard\
+   tests/pngstest-0g01 tests/pngstest-0g02 tests/pngstest-0g04\
+   tests/pngstest-0g08 tests/pngstest-0g16 tests/pngstest-2c08\
+   tests/pngstest-2c16 tests/pngstest-3p01 tests/pngstest-3p02\
+   tests/pngstest-3p04 tests/pngstest-3p08 tests/pngstest-4a08\
+   tests/pngstest-4a16 tests/pngstest-6a08 tests/pngstest-6a16\
+   tests/pngstest-error tests/pngunknown-IDAT\
+   tests/pngunknown-discard tests/pngunknown-if-safe tests/pngunknown-sAPI\
+   tests/pngunknown-sTER tests/pngunknown-save tests/pngunknown-vpAg\
+   tests/pngimage-quick tests/pngimage-full
+
+# These tests are expected, and required, to fail:
+XFAIL_TESTS = tests/pngstest-error

 # man pages
 dist_man_MANS= libpng.3 libpngpf.3 png.5
@@ -38,16 +82,15 @@ lib_LTLIBRARIES=libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c\
 	pngget.c pngmem.c pngpread.c pngread.c pngrio.c pngrtran.c pngrutil.c\
 	pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c\
-	png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+	png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h pngusr.dfa

 if PNG_ARM_NEON
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += arm/filter_neon.S
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += arm/arm_init.c\
+	arm/filter_neon.S arm/filter_neon_intrinsics.c
 endif

 nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h

-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_CPPFLAGS = @LIBPNG_DEFINES@
-
 libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined -export-dynamic \
 	-version-number @PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0

@@ -76,24 +119,33 @@ nodist_pkginclude_HEADERS= pnglibconf.h
 pkgconfigdir = @pkgconfigdir@
 pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc

-#extra source distribution files.
+# Extra source distribution files, '${srcdir}' is used below to stop build files
+# from those directories being included.  This only works if the configure is
+# not done in the source directory!
 EXTRA_DIST= \
 	ANNOUNCE CHANGES INSTALL LICENSE README TODO \
 	pngtest.png pngbar.png pngnow.png pngbar.jpg autogen.sh \
 	${srcdir}/contrib ${srcdir}/projects ${srcdir}/scripts \
-	$(TESTS) \
+	$(TESTS) $(XFAIL_TESTS) tests/pngstest \
 	CMakeLists.txt example.c libpng-manual.txt

-SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk scripts/pnglibconf.dfn
+SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk

-CLEANFILES= dfn.c dfn?.out pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
+CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
 	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
-	check.new pnglibconf.* symbols.new pngtest-log.txt \
+	check.new pnglibconf.h pngprefix.h symbols.new pngtest-log.txt \
+	pnglibconf.out pnglibconf.c pnglibconf.pre pnglibconf.dfn \
 	$(SCRIPT_CLEANFILES)

 MAINTAINERCLEANFILES = Makefile.in aclocal.m4 config.guess config.h.in \
 config.sub configure depcomp install-sh ltmain.sh missing

+# PNG_COPTS give extra options for the C compiler to be used on all compilation
+# steps (unless targe_CFLAGS is specified; that will take precedence over
+# AM_CFLAGS)
+PNG_COPTS = @PNG_COPTS@
+AM_CFLAGS = ${PNG_COPTS}
+
 # 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
@@ -101,7 +153,7 @@ config.sub configure depcomp install-sh ltmain.sh missing
 # checks for this and sets DFNCPP appropriately.
 DFNCPP = @DFNCPP@

-SUFFIXES = .chk .dfn .out
+SUFFIXES = .chk .out

 $(PNGLIB_BASENAME).pc: libpng.pc
 	cp libpng.pc $@
@@ -110,7 +162,9 @@ $(PNGLIB_BASENAME)-config: libpng-config
 	cp libpng-config $@

 scripts/sym.out scripts/vers.out: png.h pngconf.h pnglibconf.h
+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

 libpng.sym: scripts/sym.out
 	rm -f $@
@@ -118,19 +172,59 @@ libpng.sym: scripts/sym.out
 libpng.vers: scripts/vers.out
 	rm -f $@
 	cp $? $@
+
+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
+	rm -f $@
+	$(AWK) 's==0 && NR>1{print prev}\
+	   s==0{prev=$$0}\
+	   s==1{print "#define", $$1, "@PNG_PREFIX@" $$1}\
+	   s==2{print "#define @PNG_PREFIX@png_" $$1, "PNG_" $$1}\
+	   END{print prev}' s=0 pnglibconf.out s=1 scripts/prefix.out\
+	   s=2 ${srcdir}/scripts/macro.lst >pnglibconf.tf8
+	mv pnglibconf.tf8 $@
+
+pngprefix.h: scripts/intprefix.out
+	rm -f pngprefix.tf1
+	$(AWK) '{print "#define", $$1, "@PNG_PREFIX@" $$1}' $? >pngprefix.tf1
+	mv pngprefix.tf1 $@
+else
 pnglibconf.h: pnglibconf.out
 	rm -f $@
 	cp $? $@
+
+pngprefix.h: # is empty
+	:>$@
+endif
+
 $(srcdir)/scripts/pnglibconf.h.prebuilt:
 	@echo "Attempting to build $@" >&2
 	@echo "This is a machine generated file, but if you want to make" >&2
-	@echo "a new one simply make 'scripts/pnglibconf.out' and copy that" >&2
+	@echo "a new one simply make 'scripts/pnglibconf.out', copy that" >&2
+	@echo "AND set PNG_ZLIB_VERNUM to 0 (you MUST do this)" >&2
 	@exit 1

 # The following is necessary to ensure that the local pnglibconf.h is used, not
 # an installed one (this can happen immediately after on a clean system if
-# 'make test' is the first thing the user does.)
-contrib/libtests/pngvalid.o pngtest.o: pnglibconf.h
+# 'make test' is the first thing the user does.)  Only files which include
+# one of the png source files (typically png.h or pngpriv.h) need to be listed
+# here:
+pngtest.o: pnglibconf.h
+
+contrib/libtests/makepng.o: pnglibconf.h
+contrib/libtests/pngstest.o: pnglibconf.h
+contrib/libtests/pngunknown.o: pnglibconf.h
+contrib/libtests/pngimage.o: pnglibconf.h
+contrib/libtests/pngvalid.o: pnglibconf.h
+contrib/libtests/readpng.o: pnglibconf.h
+contrib/libtests/tarith.o: pnglibconf.h
+contrib/libtests/timepng.o: pnglibconf.h
+
+contrib/tools/makesRGB.o: pnglibconf.h
+contrib/tools/pngfix.o: pnglibconf.h

 # We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
 # be built with PNG_USE_READ_MACROS; this prevents the read macros from
@@ -140,51 +234,54 @@ SYMBOL_CFLAGS = -DPNGLIB_LIBNAME='PNG@PNGLIB_MAJOR@@PNGLIB_MINOR@_0'\
 		-DSYMBOL_PREFIX='$(SYMBOL_PREFIX)'\
 		-DPNG_NO_USE_READ_MACROS -DPNG_BUILDING_SYMBOL_TABLE

-.dfn.out:
-	rm -f $@ dfn.c dfn?.out
-	test -d scripts || mkdir scripts
-	echo '#include "$<"' >dfn.c
-	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) @LIBPNG_DEFINES@\
-	    $(CPPFLAGS) $(SYMBOL_CFLAGS) dfn.c > dfn1.out
-	$(SED) -n -e 's|^.*PNG_DEFN_MAGIC *-\(.*\)- *PNG_DEFN_END.*$$|\1|p'\
-	    dfn1.out >dfn2.out
-	$(SED) -e 's| *PNG_JOIN *||g' -e 's| *$$||' dfn2.out >dfn3.out
-	rm -f dfn.c dfn[12].out
-	mv dfn3.out $@
+if DO_PNG_PREFIX
+SYMBOL_CFLAGS += -DPNG_PREFIX='@PNG_PREFIX@'
+endif

-# The .dfn file for pnglibconf.h is machine generated
-pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
-	rm -f $@ dfn?.out
-	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out version=search\
+.c.out:
+	rm -f $@ $*.tf[12]
+	test -d scripts || mkdir scripts || test -d scripts
+	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES)\
+	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $< > $*.tf1
+	$(AWK) -f "${srcdir}/scripts/dfn.awk" out="$*.tf2" $*.tf1 1>&2
+	rm -f $*.tf1
+	mv $*.tf2 $@
+
+# The .c file for pnglibconf.h is machine generated
+pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+	rm -f $@ $*.tf[45]
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf4 version=search\
 	    ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
-	    $(DFA_XTRA) 1>&2
-	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn2.out dfn1.out 1>&2
-	rm dfn1.out
-	mv dfn2.out $@
+	    ${srcdir}/pngusr.dfa $(DFA_XTRA) 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf5 $*.tf4 1>&2
+	rm $*.tf4
+	mv $*.tf5 $@

 # Symbol checks (.def and .out files should match)
 scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.out
+
 .out.chk:
-	rm -f $@ symbols.new
+	rm -f $@ $*.new
 	$(AWK) -f ${srcdir}/scripts/checksym.awk ${srcdir}/scripts/${*F}.def\
-	    $< >&2
-	mv symbols.new $@
+	    of="$*.new" $< >&2
+	mv $*.new $@

 # used on demand to regenerate the standard header, CPPFLAGS should
 # be empty - no non-standard defines
-scripts/pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
-	rm -f $@ dfn?.out
+scripts/pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
+	rm -f $@ pnglibconf.tf[67]
 	test -z "$(CPPFLAGS)"
 	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
-	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out logunsupported=1
-		version=search ${srcdir}/pngconf.h -\
-		${srcdir}/scripts/pnglibconf.dfa 1>&2
-	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn2.out dfn1.out 1>&2
-	rm dfn1.out
-	mv dfn2.out $@
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf6\
+	    logunsupported=1 version=search ${srcdir}/pngconf.h -\
+	    ${srcdir}/scripts/pnglibconf.dfa 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf7\
+	    pnglibconf.tf6 1>&2
+	rm pnglibconf.tf6
+	mv pnglibconf.tf7 $@

 $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS): png.h pngconf.h \
-	pnglibconf.h pngpriv.h pngdebug.h pnginfo.h pngstruct.h
+	pnglibconf.h pngpriv.h pngdebug.h pnginfo.h pngstruct.h pngprefix.h

 test: check-am

@@ -195,34 +292,76 @@ check: scripts/symbols.chk
 dist-hook:
 	cd '$(top_distdir)'; rm -f $(SCRIPT_CLEANFILES)

-# install the .../include headers as links to the new ones
-install-data-hook:
-	cd $(DESTDIR)$(includedir); rm -f png.h pngconf.h pnglibconf.h
-	cd $(DESTDIR)$(includedir); $(LN_S) $(PNGLIB_BASENAME)/png.h png.h
-	cd $(DESTDIR)$(includedir); $(LN_S) $(PNGLIB_BASENAME)/pngconf.h \
-		pngconf.h
-	cd $(DESTDIR)$(includedir); $(LN_S) $(PNGLIB_BASENAME)/pnglibconf.h \
-		pnglibconf.h
-	cd $(DESTDIR)$(pkgconfigdir); rm -f libpng.pc
-	cd $(DESTDIR)$(pkgconfigdir); $(LN_S) $(PNGLIB_BASENAME).pc libpng.pc
+# Make links between installed files with release-specific names and the generic
+# file names.  If this install rule is run the generic names will be deleted and
+# recreated - this has obvious issues for systems with multiple installations.

-# do evil things to libpng to cause libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ to be used
-install-exec-hook:
-	cd $(DESTDIR)$(bindir); rm -f libpng-config
-	cd $(DESTDIR)$(bindir); $(LN_S) $(PNGLIB_BASENAME)-config libpng-config
-	@set -x;\
-	cd $(DESTDIR)$(libdir);\
-	for ext in a la so so.@PNGLIB_MAJOR@@PNGLIB_MINOR@.@PNGLIB_RELEASE@ sl dylib dll.a; do\
-		rm -f libpng.$$ext;\
-                if test -f $(PNGLIB_BASENAME).$$ext; then\
-                       $(LN_S) $(PNGLIB_BASENAME).$$ext libpng.$$ext;\
-                fi;\
+install-header-links:
+	@set -ex; cd '$(DESTDIR)$(includedir)'; for f in $(HEADERS); do \
+	   rm -f "$$f"; $(LN_S) "$(PNGLIB_BASENAME)/$$f" "$$f"; done
+
+uninstall-header-links:
+	cd '$(DESTDIR)$(includedir)'; rm -f $(HEADERS)
+
+install-libpng-pc:
+	@set -ex; cd '$(DESTDIR)$(pkgconfigdir)'; rm -f libpng.pc; \
+	   $(LN_S) '$(PNGLIB_BASENAME).pc' libpng.pc
+
+uninstall-libpng-pc:
+	rm -f '$(DESTDIR)$(pkgconfigdir)/libpng.pc'
+
+# EXT_LIST is a list of the possibly library directory extensions, this exists
+# because we can't find a good way of discovering the file extensions that are
+# actually installed on a given system, so instead we check for every extension
+# we have seen.
+
+EXT_LIST = a dll.a so so.@PNGLIB_MAJOR@@PNGLIB_MINOR@.@PNGLIB_RELEASE@ la sl dylib
+
+install-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)';\
+	for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext";\
+           if test -f "$(PNGLIB_BASENAME).$$ext"; then\
+              $(LN_S) "$(PNGLIB_BASENAME).$$ext" "libpng.$$ext" || exit 1;\
+           fi;\
 	done

-uninstall-hook:
-	cd $(DESTDIR)$(includedir); rm -f png.h pngconf.h pnglibconf.h
-	rm -f $(DESTDIR)$(pkgconfigdir)/libpng.pc
-	rm -f $(DESTDIR)$(bindir)/libpng-config
-	rm -f $(DESTDIR)$(libdir)/libpng.a
-	rm -f $(DESTDIR)$(libdir)/libpng.la
-	rm -f $(DESTDIR)$(libdir)/libpng.dll.a
+uninstall-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)'; for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext"; done
+
+install-libpng-config:
+	@set -ex; cd '$(DESTDIR)$(bindir)'; rm -f libpng-config; \
+	   $(LN_S) '$(PNGLIB_BASENAME)-config' libpng-config
+
+uninstall-libpng-config:
+	rm -f '$(DESTDIR)$(bindir)/libpng-config'
+
+if DO_INSTALL_LINKS
+# If --enable-unversioned-links is specified the header and lib file links
+# will be automatically made on a 'make install':
+
+install-data-hook: install-header-links
+uninstall-hook: uninstall-header-links
+install-exec-hook: install-library-links
+uninstall-hook: uninstall-library-links
+endif
+
+if DO_INSTALL_LIBPNG_PC
+# Likewise, --install-pc causes libpng.pc to be constructed:
+
+install-data-hook: install-libpng-pc
+uninstall-hook: uninstall-libpng-pc
+endif
+
+if DO_INSTALL_LIBPNG_CONFIG
+# And --install-config:
+
+install-exec-hook: install-libpng-config
+uninstall-hook: uninstall-libpng-config
+endif
+
+# The following addition ensures that 'make all' always builds the test programs
+# too.  It used to, but some change either in libpng or configure stopped this
+# working.
+all-am: $(check_PROGRAMS)
--- a/Makefile.in
+++ b/Makefile.in
--- a/63
+++ b/63
@@ -1,11 +1,11 @@
-README for libpng version 1.5.10beta01 - February 19, 2012 (shared library 15.0)
+README for libpng version 1.6.18 - July 23, 2015 (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.

-Libpng comes in several distribution formats.  Get libpng-*.tar.gz,
-libpng-*.tar.xz or libpng-*.tar.bz2 if you want UNIX-style line endings
-in the text files, or lpng*.zip if you want DOS-style line endings.
+Libpng comes in several distribution formats.  Get libpng-*.tar.gz or
+libpng-*.tar.xz or if you want UNIX-style line endings in the text files,
+or lpng*.7z or lpng*.zip if you want DOS-style line endings.

 Version 0.89 was the first official release of libpng.  Don't let the
 fact that it's the first release fool you.  The libpng library has been in
@@ -23,18 +23,25 @@ earlier versions if you are using a shared library.  The type of the
 png_uint_32, which will affect shared-library applications that use
 this function.

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

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

 Additions since 0.90 include the ability to compile libpng as a
@@ -77,17 +84,21 @@ compression library that is useful for more things than just PNG files.
 You can use zlib as a drop-in replacement for fread() and fwrite() if
 you are so inclined.

-zlib should be available at the same place that libpng is, or at.
-ftp://ftp.info-zip.org/pub/infozip/zlib
+zlib should be available at the same place that libpng is, or at zlib.net.

 You may also want a copy of the PNG specification.  It is available
 as an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find
 these at http://www.libpng.org/pub/png/documents/

 This code is currently being archived at libpng.sf.net in the
-[DOWNLOAD] area, and on CompuServe, Lib 20 (PNG SUPPORT)
-at GO GRAPHSUP.  If you can't find it in any of those places,
-e-mail me, and I'll help you find it.
+[DOWNLOAD] area, and at ftp://ftp.simplesystems.org.  If you can't find it
+in any of those places, e-mail me, and I'll help you find it.
+
+I am not a lawyer, but I believe that the Export Control Classification
+Number (ECCN) for libpng is EAR99, which means not subject to export
+controls or International Traffic in Arms Regulations (ITAR) because it
+is open source, publicly available software, that does not contain any
+encryption software.  See the EAR, paragraphs 734.3(b)(3) and 734.7(b).

 If you have any code changes, requests, problems, etc., please e-mail
 them to me.  Also, I'd appreciate any make files or project files,
@@ -105,7 +116,7 @@ based in a large way on Guy's and Andreas' earlier work), and the PNG
 development group.

 Send comments/corrections/commendations to png-mng-implement at
-lists.sourceforge.net (subscription required; visit 
+lists.sourceforge.net (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
 to subscribe) or to glennrp at users.sourceforge.net

@@ -123,7 +134,7 @@ and ...".  If in doubt, send questions to me.  I'll bounce them
 to others, if necessary.

 Please do not send suggestions on how to change PNG.  We have
-been discussing PNG for sixteen years now, and it is official and
+been discussing PNG for twenty years now, and it is official and
 finished.  If you have suggestions for libpng, however, I'll
 gladly listen.  Even if your suggestion is not used immediately,
 it may be used later.
@@ -167,23 +178,25 @@ Files in this distribution:
      pngwrite.c    =>  High-level write functions
      pngwtran.c    =>  Write data transformations
      pngwutil.c    =>  Write utility functions
+      arm           =>  Contains optimized code for the ARM platform
      contrib       =>  Contributions
+       examples         =>  Example programs
       gregbook         =>  source code for PNG reading and writing, from
                            Greg Roelofs' "PNG: The Definitive Guide",
                            O'Reilly, 1999
-       msvctest     =>  Builds and runs pngtest using a MSVC workspace
-       pngminus     =>  Simple pnm2png and png2pnm programs
-       pngsuite     =>  Test images
-       visupng      =>  Contains a MSVC workspace for VisualPng
+       libtests         =>  Test programs
+       pngminim         =>  Minimal decoder, encoder, and progressive decoder
+                            programs demonstrating use of pngusr.dfa
+       pngminus         =>  Simple pnm2png and png2pnm programs
+       pngsuite         =>  Test images
+       tools            =>  Various tools
+       visupng          =>  Contains a MSVC workspace for VisualPng
      projects      =>  Contains project files and workspaces for
                        building a DLL
-       cbuilder5        =>  Contains a Borland workspace for building
-                            libpng and zlib
-       visualc6         =>  Contains a Microsoft Visual C++ (MSVC)
-                            workspace for building libpng and zlib
+       owatcom          =>  Contains a WATCOM project for building libpng
       visualc71        =>  Contains a Microsoft Visual C++ (MSVC)
                            workspace for building libpng and zlib
-       xcode            =>  Contains an Apple xcode
+       vstudio          =>  Contains a Microsoft Visual C++ (MSVC)
                            workspace for building libpng and zlib
      scripts       =>  Directory containing scripts for building libpng:
                            (see scripts/README.txt for the list of scripts)
--- a/2
+++ b/2
@@ -6,10 +6,12 @@ Better C++ wrapper/full C++ implementation?
 Fix problem with C++ and EXTERN "C".
 cHRM transformation.
 Remove setjmp/longjmp usage in favor of returning error codes.
+Palette creation.
 Add "grayscale->palette" transformation and "palette->grayscale" detection.
 Improved dithering.
 Multi-lingual error and warning message support.
 Complete sRGB transformation (presently it simply uses gamma=0.45455).
+Make profile checking optional via a png_set_something() call.
 Man pages for function calls.
 Better documentation.
 Better filter selection
--- a/aclocal.m4
+++ b/aclocal.m4
--- a/arm/arm_init.c
+++ b/arm/arm_init.c
@@ -0,0 +1,134 @@
+
+/* arm_init.c - NEON optimised filter functions
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ * Last changed in libpng 1.6.16 [December 22, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
+ * called.
+ */
+#define _POSIX_SOURCE 1
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_ARM_NEON_OPT > 0
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
+/* WARNING: it is strongly recommended that you do not build libpng with
+ * run-time checks for CPU features if at all possible.  In the case of the ARM
+ * NEON instructions there is no processor-specific way of detecting the
+ * presence of the required support, therefore run-time detection is extremely
+ * OS specific.
+ *
+ * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing
+ * a fragment of C source code which defines the png_have_neon function.  There
+ * are a number of implementations in contrib/arm-neon, but the only one that
+ * has partial support is contrib/arm-neon/linux.c - a generic Linux
+ * implementation which reads /proc/cpufino.
+ */
+#ifndef PNG_ARM_NEON_FILE
+#  ifdef __linux__
+#     define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c"
+#  endif
+#endif
+
+#ifdef PNG_ARM_NEON_FILE
+
+#include <signal.h> /* for sig_atomic_t */
+static int png_have_neon(png_structp png_ptr);
+#include PNG_ARM_NEON_FILE
+
+#else  /* PNG_ARM_NEON_FILE */
+#  error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks"
+#endif /* PNG_ARM_NEON_FILE */
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
+
+#ifndef PNG_ALIGNED_MEMORY_SUPPORTED
+#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#endif
+
+void
+png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
+{
+   /* The switch statement is compiled in for ARM_NEON_API, the call to
+    * png_have_neon is compiled in for ARM_NEON_CHECK.  If both are defined
+    * the check is only performed if the API has not set the NEON option on
+    * or off explicitly.  In this case the check controls what happens.
+    *
+    * If the CHECK is not compiled in and the option is UNSET the behavior prior
+    * to 1.6.7 was to use the NEON code - this was a bug caused by having the
+    * wrong order of the 'ON' and 'default' cases.  UNSET now defaults to OFF,
+    * as documented in png.h
+    */
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+   switch ((pp->options >> PNG_ARM_NEON) & 3)
+   {
+      case PNG_OPTION_UNSET:
+         /* Allow the run-time check to execute if it has been enabled -
+          * thus both API and CHECK can be turned on.  If it isn't supported
+          * this case will fall through to the 'default' below, which just
+          * returns.
+          */
+#endif /* PNG_ARM_NEON_API_SUPPORTED */
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
+         {
+            static volatile sig_atomic_t no_neon = -1; /* not checked */
+
+            if (no_neon < 0)
+               no_neon = !png_have_neon(pp);
+
+            if (no_neon)
+               return;
+         }
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+         break;
+#endif
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
+
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+      default: /* OFF or INVALID */
+         return;
+
+      case PNG_OPTION_ON:
+         /* Option turned on */
+         break;
+   }
+#endif
+
+   /* IMPORTANT: any new external functions used here must be declared using
+    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
+    * 'prefix' option to configure works:
+    *
+    *    ./configure --with-libpng-prefix=foobar_
+    *
+    * Verify you have got this right by running the above command, doing a build
+    * and examining pngprefix.h; it must contain a #define for every external
+    * function you add.  (Notice that this happens automatically for the
+    * initialization function.)
+    */
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
+
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth3_neon;
+   }
+
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+          png_read_filter_row_paeth4_neon;
+   }
+}
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* READ */
--- a/arm/filter_neon.S
+++ b/arm/filter_neon.S
@@ -1,18 +1,36 @@

 /* filter_neon.S - NEON optimised filter functions
 *
- * Copyright (c) 2011 Glenn Randers-Pehrson
+ * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by Mans Rullgard, 2011.
+ * Last changed in libpng 1.6.16 [December 22, 2014]
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
 */

+/* This is required to get the symbol renames, which are #defines, and the
+ * definitions (or not) of PNG_ARM_NEON_OPT and PNG_ARM_NEON_IMPLEMENTATION.
+ */
+#define PNG_VERSION_INFO_ONLY
+#include "../pngpriv.h"
+
 #if defined(__linux__) && defined(__ELF__)
 .section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
 #endif

+#ifdef PNG_READ_SUPPORTED
+
+/* Assembler NEON support - only works for 32-bit ARM (i.e. it does not work for
+ * ARM64).  The code in arm/filter_neon_intrinsics.c supports ARM64, however it
+ * only works if -mfpu=neon is specified on the GCC command line.  See pngpriv.h
+ * for the logic which sets PNG_USE_ARM_NEON_ASM:
+ */
+#if PNG_ARM_NEON_IMPLEMENTATION == 2 /* hand-coded assembler */
+
+#if PNG_ARM_NEON_OPT > 0
+
 #ifdef __ELF__
 #   define ELF
 #else
@@ -29,6 +47,13 @@ ELF     .size   \name, . - \name
        .purgem endfunc
    .endm
        .text
+
+        /* Explicitly specifying alignment here because some versions of
+         * GAS don't align code correctly.  This is harmless in correctly
+         * written versions of GAS.
+         */
+        .align 2
+
    .if \export
        .global \name
    .endif
@@ -223,3 +248,6 @@ func    png_read_filter_row_paeth3_neon, export=1

        pop             {r4,pc}
 endfunc
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* PNG_ARM_NEON_IMPLEMENTATION == 2 (assembler) */
+#endif /* READ */
--- a/arm/filter_neon_intrinsics.c
+++ b/arm/filter_neon_intrinsics.c
@@ -0,0 +1,373 @@
+
+/* filter_neon_intrinsics.c - NEON optimised filter functions
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by James Yu <james.yu at linaro.org>, October 2013.
+ * Based on filter_neon.S, written by Mans Rullgard, 2011.
+ *
+ * Last changed in libpng 1.6.16 [December 22, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* This code requires -mfpu=neon on the command line: */
+#if PNG_ARM_NEON_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+#include <arm_neon.h>
+
+/* libpng row pointers are not necessarily aligned to any particular boundary,
+ * however this code will only work with appropriate alignment.  arm/arm_init.c
+ * checks for this (and will not compile unless it is done). This code uses
+ * variants of png_aligncast to avoid compiler warnings.
+ */
+#define png_ptr(type,pointer) png_aligncast(type *,pointer)
+#define png_ptrc(type,pointer) png_aligncastconst(const type *,pointer)
+
+/* The following relies on a variable 'temp_pointer' being declared with type
+ * 'type'.  This is written this way just to hide the GCC strict aliasing
+ * warning; note that the code is safe because there never is an alias between
+ * the input and output pointers.
+ */
+#define png_ldr(type,pointer)\
+   (temp_pointer = png_ptr(type,pointer), *temp_pointer)
+
+#if PNG_ARM_NEON_OPT > 0
+
+void
+png_read_filter_row_up_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+   png_const_bytep pp = prev_row;
+
+   for (; rp < rp_stop; rp += 16, pp += 16)
+   {
+      uint8x16_t qrp, qpp;
+
+      qrp = vld1q_u8(rp);
+      qpp = vld1q_u8(pp);
+      qrp = vaddq_u8(qrp, qpp);
+      vst1q_u8(rp, qrp);
+   }
+}
+
+void
+png_read_filter_row_sub3_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x16_t vtmp = vld1q_u8(rp);
+   uint8x8x2_t *vrpt = png_ptr(uint8x8x2_t, &vtmp);
+   uint8x8x2_t vrp = *vrpt;
+
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   for (; rp < rp_stop;)
+   {
+      uint8x8_t vtmp1, vtmp2;
+      uint32x2_t *temp_pointer;
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+      vdest.val[0] = vadd_u8(vdest.val[3], vrp.val[0]);
+      vtmp2 = vext_u8(vrp.val[0], vrp.val[1], 6);
+      vdest.val[1] = vadd_u8(vdest.val[0], vtmp1);
+
+      vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+      vdest.val[2] = vadd_u8(vdest.val[1], vtmp2);
+      vdest.val[3] = vadd_u8(vdest.val[2], vtmp1);
+
+      vtmp = vld1q_u8(rp + 12);
+      vrpt = png_ptr(uint8x8x2_t, &vtmp);
+      vrp = *vrpt;
+
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+      rp += 3;
+   }
+
+   PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_sub4_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   for (; rp < rp_stop; rp += 16)
+   {
+      uint32x2x4_t vtmp = vld4_u32(png_ptr(uint32_t,rp));
+      uint8x8x4_t *vrpt = png_ptr(uint8x8x4_t,&vtmp);
+      uint8x8x4_t vrp = *vrpt;
+      uint32x2x4_t *temp_pointer;
+
+      vdest.val[0] = vadd_u8(vdest.val[3], vrp.val[0]);
+      vdest.val[1] = vadd_u8(vdest.val[0], vrp.val[1]);
+      vdest.val[2] = vadd_u8(vdest.val[1], vrp.val[2]);
+      vdest.val[3] = vadd_u8(vdest.val[2], vrp.val[3]);
+      vst4_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2x4_t,&vdest), 0);
+   }
+
+   PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_avg3_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x16_t vtmp;
+   uint8x8x2_t *vrpt;
+   uint8x8x2_t vrp;
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   vtmp = vld1q_u8(rp);
+   vrpt = png_ptr(uint8x8x2_t,&vtmp);
+   vrp = *vrpt;
+
+   for (; rp < rp_stop; pp += 12)
+   {
+      uint8x8_t vtmp1, vtmp2, vtmp3;
+
+      uint8x8x2_t *vppt;
+      uint8x8x2_t vpp;
+
+      uint32x2_t *temp_pointer;
+
+      vtmp = vld1q_u8(pp);
+      vppt = png_ptr(uint8x8x2_t,&vtmp);
+      vpp = *vppt;
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+      vdest.val[0] = vhadd_u8(vdest.val[3], vpp.val[0]);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+
+      vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 3);
+      vtmp3 = vext_u8(vrp.val[0], vrp.val[1], 6);
+      vdest.val[1] = vhadd_u8(vdest.val[0], vtmp2);
+      vdest.val[1] = vadd_u8(vdest.val[1], vtmp1);
+
+      vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 6);
+      vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+
+      vtmp = vld1q_u8(rp + 12);
+      vrpt = png_ptr(uint8x8x2_t,&vtmp);
+      vrp = *vrpt;
+
+      vdest.val[2] = vhadd_u8(vdest.val[1], vtmp2);
+      vdest.val[2] = vadd_u8(vdest.val[2], vtmp3);
+
+      vtmp2 = vext_u8(vpp.val[1], vpp.val[1], 1);
+
+      vdest.val[3] = vhadd_u8(vdest.val[2], vtmp2);
+      vdest.val[3] = vadd_u8(vdest.val[3], vtmp1);
+
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+      rp += 3;
+   }
+}
+
+void
+png_read_filter_row_avg4_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+   png_const_bytep pp = prev_row;
+
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   for (; rp < rp_stop; rp += 16, pp += 16)
+   {
+      uint32x2x4_t vtmp;
+      uint8x8x4_t *vrpt, *vppt;
+      uint8x8x4_t vrp, vpp;
+      uint32x2x4_t *temp_pointer;
+
+      vtmp = vld4_u32(png_ptr(uint32_t,rp));
+      vrpt = png_ptr(uint8x8x4_t,&vtmp);
+      vrp = *vrpt;
+      vtmp = vld4_u32(png_ptrc(uint32_t,pp));
+      vppt = png_ptr(uint8x8x4_t,&vtmp);
+      vpp = *vppt;
+
+      vdest.val[0] = vhadd_u8(vdest.val[3], vpp.val[0]);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+      vdest.val[1] = vhadd_u8(vdest.val[0], vpp.val[1]);
+      vdest.val[1] = vadd_u8(vdest.val[1], vrp.val[1]);
+      vdest.val[2] = vhadd_u8(vdest.val[1], vpp.val[2]);
+      vdest.val[2] = vadd_u8(vdest.val[2], vrp.val[2]);
+      vdest.val[3] = vhadd_u8(vdest.val[2], vpp.val[3]);
+      vdest.val[3] = vadd_u8(vdest.val[3], vrp.val[3]);
+
+      vst4_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2x4_t,&vdest), 0);
+   }
+}
+
+static uint8x8_t
+paeth(uint8x8_t a, uint8x8_t b, uint8x8_t c)
+{
+   uint8x8_t d, e;
+   uint16x8_t p1, pa, pb, pc;
+
+   p1 = vaddl_u8(a, b); /* a + b */
+   pc = vaddl_u8(c, c); /* c * 2 */
+   pa = vabdl_u8(b, c); /* pa */
+   pb = vabdl_u8(a, c); /* pb */
+   pc = vabdq_u16(p1, pc); /* pc */
+
+   p1 = vcleq_u16(pa, pb); /* pa <= pb */
+   pa = vcleq_u16(pa, pc); /* pa <= pc */
+   pb = vcleq_u16(pb, pc); /* pb <= pc */
+
+   p1 = vandq_u16(p1, pa); /* pa <= pb && pa <= pc */
+
+   d = vmovn_u16(pb);
+   e = vmovn_u16(p1);
+
+   d = vbsl_u8(d, b, c);
+   e = vbsl_u8(e, a, d);
+
+   return e;
+}
+
+void
+png_read_filter_row_paeth3_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x16_t vtmp;
+   uint8x8x2_t *vrpt;
+   uint8x8x2_t vrp;
+   uint8x8_t vlast = vdup_n_u8(0);
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   vtmp = vld1q_u8(rp);
+   vrpt = png_ptr(uint8x8x2_t,&vtmp);
+   vrp = *vrpt;
+
+   for (; rp < rp_stop; pp += 12)
+   {
+      uint8x8x2_t *vppt;
+      uint8x8x2_t vpp;
+      uint8x8_t vtmp1, vtmp2, vtmp3;
+      uint32x2_t *temp_pointer;
+
+      vtmp = vld1q_u8(pp);
+      vppt = png_ptr(uint8x8x2_t,&vtmp);
+      vpp = *vppt;
+
+      vdest.val[0] = paeth(vdest.val[3], vpp.val[0], vlast);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+      vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 3);
+      vdest.val[1] = paeth(vdest.val[0], vtmp2, vpp.val[0]);
+      vdest.val[1] = vadd_u8(vdest.val[1], vtmp1);
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 6);
+      vtmp3 = vext_u8(vpp.val[0], vpp.val[1], 6);
+      vdest.val[2] = paeth(vdest.val[1], vtmp3, vtmp2);
+      vdest.val[2] = vadd_u8(vdest.val[2], vtmp1);
+
+      vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+      vtmp2 = vext_u8(vpp.val[1], vpp.val[1], 1);
+
+      vtmp = vld1q_u8(rp + 12);
+      vrpt = png_ptr(uint8x8x2_t,&vtmp);
+      vrp = *vrpt;
+
+      vdest.val[3] = paeth(vdest.val[2], vtmp2, vtmp3);
+      vdest.val[3] = vadd_u8(vdest.val[3], vtmp1);
+
+      vlast = vtmp2;
+
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+      rp += 3;
+   }
+}
+
+void
+png_read_filter_row_paeth4_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+   png_const_bytep pp = prev_row;
+
+   uint8x8_t vlast = vdup_n_u8(0);
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   for (; rp < rp_stop; rp += 16, pp += 16)
+   {
+      uint32x2x4_t vtmp;
+      uint8x8x4_t *vrpt, *vppt;
+      uint8x8x4_t vrp, vpp;
+      uint32x2x4_t *temp_pointer;
+
+      vtmp = vld4_u32(png_ptr(uint32_t,rp));
+      vrpt = png_ptr(uint8x8x4_t,&vtmp);
+      vrp = *vrpt;
+      vtmp = vld4_u32(png_ptrc(uint32_t,pp));
+      vppt = png_ptr(uint8x8x4_t,&vtmp);
+      vpp = *vppt;
+
+      vdest.val[0] = paeth(vdest.val[3], vpp.val[0], vlast);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+      vdest.val[1] = paeth(vdest.val[0], vpp.val[1], vpp.val[0]);
+      vdest.val[1] = vadd_u8(vdest.val[1], vrp.val[1]);
+      vdest.val[2] = paeth(vdest.val[1], vpp.val[2], vpp.val[1]);
+      vdest.val[2] = vadd_u8(vdest.val[2], vrp.val[2]);
+      vdest.val[3] = paeth(vdest.val[2], vpp.val[3], vpp.val[2]);
+      vdest.val[3] = vadd_u8(vdest.val[3], vrp.val[3]);
+
+      vlast = vpp.val[3];
+
+      vst4_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2x4_t,&vdest), 0);
+   }
+}
+
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* PNG_ARM_NEON_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */
--- a/autogen.sh
+++ b/autogen.sh
@@ -1,34 +1,225 @@
 #! /bin/sh
-# a quick hack script to generate necessary files from 
-# auto* tools.
 #
-# WARNING: if you run this you will change the versions
-# of the tools which are used and, maybe, required!
+# Run 'autoreconf' to build 'configure', 'Makefile.in' and other configure
+# control files.
+#
+# The first time this is run on a GIT checkout the only files that exist are
+# configure.ac and Makefile.am; all of the autotools support scripts are
+# missing.  They are instantiated with autoreconf --force --install.
+#
+# For regular ("tarball") distributions all the files should exist.  We do not
+# want them to be updated *under any circumstances*.  It should never be
+# necessary to run autogen.sh because ./configure --enable-maintainer-mode says
+# what to do if Makefile.am or configure.ac are changed.
+#
+# It is *probably* OK to update the files on a GIT checkout, because they have
+# come from the local tools, but leave that to the user who is assumed to know
+# whether it is ok or required.
+#
+# This script is intended to work without arguments, there are, however, hidden
+# arguments (a) for use while testing the script and (b) to fix up systems that
+# have been broken.  If (b) is required the script prompts for the correct
+# options.  For this reason the options are *NOT* documented in the help; this
+# is deliberate; UTSL.
+#
+clean=
+maintainer=
+while test $# -gt 0
+do
+   case "$1" in
+      --maintainer)
+         maintainer=1;;

-# You can define your own replacements in your environment.
-# $AUTOCONF,  $AUTOMAKE, $AUTOHEADER, $AUTOPOINT, $ACLOCAL and $LIBTOOLIZE
+      --clean)
+         clean=1;;

-touch Makefile.am configure.ac
-{
-   LT=${LIBTOOLIZE-libtoolize}
-   echo "running $LT" >&2
-   $LT --force --copy --automake
-} && {
-   AL=${ACLOCAL-aclocal}
-   echo "running $AL" >&2
-   $AL
-} && {
-   AH=${AUTOHEADER-autoheader}
-   echo "running $AH [ignore the warnings]" >&2
-   $AH
-} && {
-   AM=${AUTOMAKE-automake}
-   echo "running $AM" >&2
-   $AM --force-missing --foreign -a -c
-} && {
-   AC=${AUTOCONF-autoconf}
-   echo "running $AC" >&2
-   $AC
-} &&
-   echo "autogen complete" >&2 ||
-   echo "ERROR: autogen.sh failed, autogen is incomplete" >&2
+      *)
+         exec >&2
+         echo "$0: usage: ./autogen.sh"
+         if test -d .git
+         then
+            echo "  ./autogen.sh generates the configure script and"
+            echo "  Makefile.in, or refreshes them after changes to Makefile.am"
+            echo "  or configure.ac.  You may prefer to just run autoreconf."
+         elif test -z "$maintainer"
+         then
+            echo "  DO NOT RUN THIS SCRIPT."
+            echo "  If you need to change Makefile.am or configure.ac then you"
+            echo "  also need to run ./configure --enable-maintainer-mode and"
+            echo "  use the appropriate autotools, *NOT* this script, to update"
+            echo "  everything, please check the documentation of autoreconf."
+            echo "  WARNING: libpng is intentionally generated with a known,"
+            echo "  fixed, set of autotools.  It is known *NOT* to work with"
+            echo "  the collection of autotools distributed on highly reputable"
+            echo "  operating systems."
+            echo "  Remember: autotools is GNU software, you are expected to"
+            echo "  pay for support."
+         else
+            echo "  You have run autogen.sh with --maintainer enabled and you"
+            echo "  are not using a GIT distribution, then you have given an"
+            echo "  unrecognized argument.  This is not good. --maintainer"
+            echo "  switches off any assumptions that you might not know what"
+            echo "  you are doing."
+         fi
+         exit 1;;
+   esac
+
+   shift
+done
+#
+# First check for a set of the autotools files; if absent then this is assumed
+# to be a GIT version and the local autotools must be used.  If present this
+# is a tarball distribution and the script should not be used.  If partially
+# present bad things are happening.
+#
+# The autotools generated files:
+libpng_autotools_files="Makefile.in aclocal.m4 config.guess config.h.in
+   config.h.in~ config.sub configure depcomp install-sh ltmain.sh missing\
+   test-driver"
+#
+# Files generated by versions of configue >2.68 or automake >1.13 (i.e. later
+# versions than those required by configure.ac):
+libpng_autotools_extra="compile"
+#
+# These are separate because 'maintainer-clean' does not remove them.
+libpng_libtool_files="scripts/libtool.m4 scripts/ltoptions.m4\
+   scripts/ltsugar.m4 scripts/ltversion.m4 scripts/lt~obsolete.m4"
+
+libpng_autotools_dirs="autom4te.cache" # not required
+#
+# The configure generated files:
+libpng_configure_files="Makefile config.h config.log config.status\
+   libpng-config libpng.pc libtool stamp-h1"
+
+libpng_configure_dirs=".deps"
+#
+# We must remove the configure generated files as well as the autotools
+# generated files if autotools are regenerated because otherwise if configure
+# has been run without "--enable-maintainer-mode" make can do a partial update
+# of Makefile.  These functions do the two bits of cleaning.
+clean_autotools(){
+   rm -rf $libpng_autotools_files $libpng_libtool_files $libpng_autotools_dirs
+   rm -rf $libpng_autotools_extra
+}
+
+clean_configure(){
+   rm -rf $libpng_configure_files $libpng_configure_dirs
+}
+#
+# Clean: remove everything (this is to help with testing)
+if test -n "$clean"
+then
+   clean_configure
+   if test -n "$maintainer"
+   then
+      clean_autotools
+   fi
+
+   exit 0
+fi
+#
+# Validate the distribution.
+libpng_autotools_file_found=
+libpng_autotools_file_missing=
+for file in $libpng_autotools_files
+do
+   if test -f  "$file"
+   then
+      libpng_autotools_file_found=1
+   else
+      libpng_autotools_file_missing=1
+   fi
+done
+#
+# Presence of one of these does not *invalidate* missing, but absence
+# invalidates found.
+for file in $libpng_libtool_files
+do
+   if test ! -f "$file"
+   then
+      libpng_autotools_file_missing=1
+   fi
+done
+#
+# The cache directory doesn't matter - it will be regenerated and does not exist
+# anyway in a tarball.
+#
+# Either everything is missing or everything is there, the --maintainer option
+# just changes this so that the mode is set to generate all the files.
+mode=
+if test -z "$libpng_autotools_file_found" -o -n "$maintainer"
+then
+   mode="autoreconf"
+else
+   if test -n "$libpng_autotools_file_missing"
+   then
+      mode="broken"
+   else
+      mode="configure"
+   fi
+fi
+#
+# So:
+case "$mode" in
+   autoreconf)
+      # Clean in case configure files exist
+      clean_configure
+      clean_autotools
+      # Everything must be initialized, so use --force
+      if autoreconf --warnings=all --force --install
+      then
+         missing=
+         for file in $libpng_autotools_files
+         do
+            test -f "$file" || missing=1
+         done
+         # ignore the cache directory
+         test -z "$missing" || {
+            exec >&2
+            echo "autoreconf was run, but did not produce all the expected"
+            echo "files.  It is likely that your autotools installation is"
+            echo "not compatible with that expected by libpng."
+            exit 1
+         }
+      else
+         exec >&2
+         echo "autoreconf failed: your version of autotools is incompatible"
+         echo "with this libpng version.  Please use a distributed archive"
+         echo "(which includes the autotools generated files) and run configure"
+         echo "instead."
+         exit 1
+      fi;;
+
+   configure)
+      if test -d .git
+      then
+         exec >&2
+         echo "ERROR: running autoreconf on an initialized sytem"
+         echo "  This is not necessary; it is only necessary to remake the"
+         echo "  autotools generated files if Makefile.am or configure.ac"
+         echo "  change and make does the right thing with:"
+         echo
+         echo "     ./configure --enable-maintainer-mode."
+         echo
+         echo "  You can run autoreconf yourself if you don't like maintainer"
+         echo "  mode and you can also just run autoreconf -f -i to initialize"
+         echo "  everything in the first place; this script is only for"
+         echo "  compatibility with prior releases."
+         exit 1
+      else
+         exec >&2
+         echo "autogen.sh is intended only to generate 'configure' on systems"
+         echo "that do not have it.  You have a complete 'configure', if you"
+         echo "need to change Makefile.am or configure.ac you also need to"
+         echo "run configure with the --enable-maintainer-mode option."
+         exit 1
+      fi;;
+
+   broken)
+      exec >&2
+      echo "Your system has a partial set of autotools generated files."
+      echo "autogen.sh is unable to proceed.  The full set of files is"
+      echo "contained in the libpng 'tar' distribution archive and you do"
+      echo "not need to run autogen.sh if you use it."
+      exit 1;;
+esac
--- a/config.guess
+++ b/config.guess
--- a/config.h.in
+++ b/config.h.in
@@ -1,109 +0,0 @@
-/* config.h.in.  Generated from configure.ac by autoheader.  */
-
-/* Define to 1 if you have the <dlfcn.h> header file. */
-#undef HAVE_DLFCN_H
-
-/* Define to 1 if you have the `feenableexcept' function. */
-#undef HAVE_FEENABLEEXCEPT
-
-/* Define to 1 if you have the <inttypes.h> header file. */
-#undef HAVE_INTTYPES_H
-
-/* Define to 1 if you have the `m' library (-lm). */
-#undef HAVE_LIBM
-
-/* Define to 1 if you have the `z' library (-lz). */
-#undef HAVE_LIBZ
-
-/* Define to 1 if you have the <malloc.h> header file. */
-#undef HAVE_MALLOC_H
-
-/* Define to 1 if you have the <memory.h> header file. */
-#undef HAVE_MEMORY_H
-
-/* Define to 1 if you have the `memset' function. */
-#undef HAVE_MEMSET
-
-/* Define to 1 if you have the `pow' function. */
-#undef HAVE_POW
-
-/* Define to 1 if you have the <stdint.h> header file. */
-#undef HAVE_STDINT_H
-
-/* Define to 1 if you have the <stdlib.h> header file. */
-#undef HAVE_STDLIB_H
-
-/* Define to 1 if you have the <strings.h> header file. */
-#undef HAVE_STRINGS_H
-
-/* Define to 1 if you have the <string.h> header file. */
-#undef HAVE_STRING_H
-
-/* Define to 1 if you have the <sys/stat.h> header file. */
-#undef HAVE_SYS_STAT_H
-
-/* Define to 1 if you have the <sys/types.h> header file. */
-#undef HAVE_SYS_TYPES_H
-
-/* Define to 1 if you have the <unistd.h> header file. */
-#undef HAVE_UNISTD_H
-
-/* Define to the sub-directory in which libtool stores uninstalled libraries.
-   */
-#undef LT_OBJDIR
-
-/* Name of package */
-#undef PACKAGE
-
-/* Define to the address where bug reports for this package should be sent. */
-#undef PACKAGE_BUGREPORT
-
-/* Define to the full name of this package. */
-#undef PACKAGE_NAME
-
-/* Define to the full name and version of this package. */
-#undef PACKAGE_STRING
-
-/* Define to the one symbol short name of this package. */
-#undef PACKAGE_TARNAME
-
-/* Define to the home page for this package. */
-#undef PACKAGE_URL
-
-/* Define to the version of this package. */
-#undef PACKAGE_VERSION
-
-/* Align row buffers */
-#undef PNG_ALIGNED_MEMORY_SUPPORTED
-
-/* Enable ARM NEON optimizations */
-#undef PNG_ARM_NEON
-
-/* Define to 1 if you have the ANSI C header files. */
-#undef STDC_HEADERS
-
-/* Define to 1 if your <sys/time.h> declares `struct tm'. */
-#undef TM_IN_SYS_TIME
-
-/* Version number of package */
-#undef VERSION
-
-/* Define to empty if `const' does not conform to ANSI C. */
-#undef const
-
-/* Define to the equivalent of the C99 'restrict' keyword, or to
-   nothing if this is not supported.  Do not define if restrict is
-   supported directly.  */
-#undef restrict
-/* Work around a bug in Sun C++: it does not support _Restrict or
-   __restrict__, even though the corresponding Sun C compiler ends up with
-   "#define restrict _Restrict" or "#define restrict __restrict__" in the
-   previous line.  Perhaps some future version of Sun C++ will work with
-   restrict; if so, hopefully it defines __RESTRICT like Sun C does.  */
-#if defined __SUNPRO_CC && !defined __RESTRICT
-# define _Restrict
-# define __restrict__
-#endif
-
-/* Define to `unsigned int' if <sys/types.h> does not define. */
-#undef size_t
--- a/config.sub
+++ b/config.sub
--- a/15261
+++ b/15261
--- a/configure.ac
+++ b/configure.ac
@@ -14,63 +14,101 @@ dnl Makefile.am to upgrade the package name.
 dnl This is here to prevent earlier autoconf from being used, it
 dnl should not be necessary to regenerate configure if the time
 dnl stamps are correct
-AC_PREREQ(2.59)
+AC_PREREQ([2.68])

 dnl Version number stuff here:

-AC_INIT([libpng], [1.5.10beta01], [png-mng-implement@lists.sourceforge.net])
-AM_INIT_AUTOMAKE
-dnl stop configure from automagically running automake
+AC_INIT([libpng],[1.6.18],[png-mng-implement@lists.sourceforge.net])
+AC_CONFIG_MACRO_DIR([scripts])
+
+# libpng does not follow GNU file name conventions (hence 'foreign')
+# color-tests requires automake 1.11 or later
+# silent-rules requires automake 1.11 or later
+# dist-xz requires automake 1.11 or later
+# 1.12.2 fixes a security issue in 1.11.2 and 1.12.1
+# 1.13 is required for parallel tests
+AM_INIT_AUTOMAKE([1.13 foreign dist-xz color-tests silent-rules subdir-objects])
+# The following line causes --disable-maintainer-mode to be the default to
+# configure, this is necessary because libpng distributions cannot rely on the
+# time stamps of the autotools generated files being correct
 AM_MAINTAINER_MODE

-PNGLIB_VERSION=1.5.10beta01
+dnl configure.ac and Makefile.am expect automake 1.11.2 or a compatible later
+dnl version; aclocal.m4 will generate a failure if you use a prior version of
+dnl automake, so the following is not necessary (and is not defined anyway):
+dnl AM_PREREQ([1.11.2])
+dnl stop configure from automagically running automake
+
+PNGLIB_VERSION=1.6.18
 PNGLIB_MAJOR=1
-PNGLIB_MINOR=5
-PNGLIB_RELEASE=10
+PNGLIB_MINOR=6
+PNGLIB_RELEASE=18

 dnl End of version number stuff

 AC_CONFIG_SRCDIR([pngget.c])
-AM_CONFIG_HEADER(config.h)
+AC_CONFIG_HEADERS([config.h])

 # Checks for programs.
 AC_LANG([C])
 AC_PROG_CC
 AM_PROG_AS
-AC_PROG_LD
+LT_PATH_LD
 AC_PROG_CPP
-AC_CHECK_TOOL(SED, sed, :)
-AC_CHECK_TOOL(AWK, awk, :)
+AC_PROG_AWK
 AC_PROG_INSTALL
 AC_PROG_LN_S
 AC_PROG_MAKE_SET
-LT_INIT([win32-dll])

-# On Solaris 10 and 12 CPP gets set to cc -E, however this still
-# does some input parsing.  We need strict ANSI-C style tokenization,
-# check this:
-AC_REQUIRE_CPP
-AC_MSG_CHECKING([for a C preprocessor that does not parse its input])
-AC_TRY_CPP([1.5.0 16BIT],
-   [DFNCPP="$CPP"],
-   [DFNCPP=""
-   sav_CPP="$CPP"
-   for CPP in "${CC-cc} -E" "${CC-cc} -E -traditional-cpp" "/lib/cpp" "cpp"; do
-      AC_TRY_CPP([1.5.0 16BIT],
-         [DFNCPP="$CPP"]
-         [break],,)
-   done
-   CPP="$sav_CPP"])
-if test -n "$DFNCPP"; then
-   AC_MSG_RESULT([$DFNCPP])
-   AC_SUBST(DFNCPP)
+dnl libtool/libtoolize; version 2.4.2 is the tested version, this or any
+dnl compatible later version may be used
+LT_INIT([win32-dll])
+LT_PREREQ([2.4.2])
+
+# Some awks crash when confronted with pnglibconf.dfa, do a test run now
+# to make sure this doesn't happen
+AC_MSG_CHECKING([that AWK works])
+if ${AWK} -f ${srcdir}/scripts/options.awk out="/dev/null" version=search\
+   ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+   ${srcdir}/pngusr.dfa 1>&2
+then
+   AC_MSG_RESULT([ok])
 else
-   AC_MSG_FAILURE([not found], 1)
+   AC_MSG_FAILURE([failed], 1)
 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="$CPP"
+AC_SUBST(DFNCPP)
+
+# -Werror cannot be passed to GCC in CFLAGS because configure will fail (it
+# checks the compiler with a program that generates a warning), add the
+# following option to deal with this
+AC_ARG_VAR(PNG_COPTS,
+   [additional flags for the C compiler, use this for options that would]
+   [cause configure itself to fail])
+AC_ARG_ENABLE(werror,
+   AS_HELP_STRING([[[--enable-werror[=OPT]]]],
+      [Pass -Werror or the given argument to the compiler if it is supported]),
+   [test "$enable_werror" = "yes" && enable_werror="-Werror"
+    if test "$enable_werror" != "no"; then
+      sav_CFLAGS="$CFLAGS"
+      CFLAGS="$enable_werror $CFLAGS"
+      AC_MSG_CHECKING([if the compiler allows $enable_werror])
+      AC_COMPILE_IFELSE(
+         [AC_LANG_SOURCE([
+            [int main(int argc, char **argv){]
+            [return argv[argc-1][0];]
+            [}]])],
+         AC_MSG_RESULT(yes)
+         PNG_COPTS="$PNG_COPTS $enable_werror",
+         AC_MSG_RESULT(no))
+      CFLAGS="$sav_CFLAGS"
+    fi],)
+
 # Checks for header files.
 AC_HEADER_STDC
-AC_CHECK_HEADERS([malloc.h stdlib.h string.h strings.h])

 # Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
@@ -80,16 +118,15 @@ AC_C_RESTRICT

 # Checks for library functions.
 AC_FUNC_STRTOD
-AC_CHECK_FUNCS([memset], , AC_ERROR([memset not found in libc]))
-AC_CHECK_FUNCS([pow], , AC_CHECK_LIB(m, pow, , AC_ERROR([cannot find pow])) )
+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,
-   AC_HELP_STRING([--with-zlib-prefix],
-                  [prefix that may have been used in installed zlib]),
-                  [ZPREFIX=${withval}],
-                  [ZPREFIX='z_'])
+   AS_HELP_STRING([[[--with-zlib-prefix]]],
+      [prefix that may have been used in installed zlib]),
+      [ZPREFIX=${withval}],
+      [ZPREFIX='z_'])
 AC_CHECK_LIB(z, zlibVersion, ,
-    AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, ,
-                 AC_ERROR([zlib not installed])))
+    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
@@ -97,10 +134,6 @@ AC_CHECK_LIB(z, zlibVersion, ,
 AC_CHECK_LIB([m], [feenableexcept])
 AC_CHECK_FUNCS([feenableexcept])

-LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG
-LIBPNG_DEFINES=$LIBPNG_DEFINES
-AC_SUBST(LIBPNG_DEFINES)
-
 AC_MSG_CHECKING([if using Solaris linker])
 SLD=`$LD --version 2>&1 | grep Solaris`
 if test "$SLD"; then
@@ -145,9 +178,9 @@ AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$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__" \
-                   | ${CPP-${CC-gcc} -E} - 2>&1 \
-                   | ${EGREP-grep} "^PREFIX=" \
-                   | ${SED-sed} "s:^PREFIX=::"`
+                  | ${CPP-${CC-gcc} -E} - 2>&1 \
+                  | ${EGREP-grep} "^PREFIX=" \
+                  | ${SED-sed} -e "s:^PREFIX=::" -e "s:__USER_LABEL_PREFIX__::"`
    AC_SUBST(SYMBOL_PREFIX)
    AC_MSG_RESULT($SYMBOL_PREFIX)
 fi
@@ -161,44 +194,131 @@ AC_SUBST(PNGLIB_RELEASE)
 # Additional arguments (and substitutions)
 # Allow the pkg-config directory to be set
 AC_ARG_WITH(pkgconfigdir,
-	AC_HELP_STRING([--with-pkgconfigdir],
-	[Use the specified pkgconfig dir (default is libdir/pkgconfig)]),
-	[pkgconfigdir=${withval}],
-	[pkgconfigdir='${libdir}/pkgconfig'])
+   AS_HELP_STRING([[[--with-pkgconfigdir]]],
+      [Use the specified pkgconfig dir (default is libdir/pkgconfig)]),
+   [pkgconfigdir=${withval}],
+   [pkgconfigdir='${libdir}/pkgconfig'])

 AC_SUBST([pkgconfigdir])
-AC_MSG_NOTICE([pkgconfig directory is ${pkgconfigdir}])
+AC_MSG_NOTICE([[pkgconfig directory is ${pkgconfigdir}]])

 # Make the *-config binary config scripts optional
 AC_ARG_WITH(binconfigs,
-	AC_HELP_STRING([--with-binconfigs],
-		[Generate shell libpng-config scripts as well as pkg-config data]
-		[@<:@default=yes@:>@]),
-	[if test "${withval}" = no; then
-		binconfigs=
-		AC_MSG_NOTICE([libpng-config scripts will not be built])
-	else
-		binconfigs='${binconfigs}'
-	fi],
-	[binconfigs='${binconfigs}'])
+   AS_HELP_STRING([[[--with-binconfigs]]],
+      [Generate shell libpng-config scripts as well as pkg-config data]
+      [@<:@default=yes@:>@]),
+   [if test "${withval}" = no; then
+      binconfigs=
+      AC_MSG_NOTICE([[libpng-config scripts will not be built]])
+    else
+      binconfigs='${binconfigs}'
+    fi],
+   [binconfigs='${binconfigs}'])
 AC_SUBST([binconfigs])

-# Because GCC by default assembles code with an executable stack, even though it
-# compiles C code with a non-executable stack, it is necessary to do a fixup
-# here (this may by GCC specific)
-AC_SUBST([AM_CCASFLAGS], [-Wa,--noexecstack])
+# Support for prefixes to the API function names; this will generate defines
+# at the start of the build to rename exported library functions
+AC_ARG_WITH(libpng-prefix,
+   AS_HELP_STRING([[[--with-libpng-prefix]]],
+      [prefix libpng exported function (API) names with the given value]),
+   [if test "${withval:-no}" != "no"; then
+      AC_SUBST([PNG_PREFIX], [${withval}])
+    fi])
+AM_CONDITIONAL([DO_PNG_PREFIX], [test "${with_libpng_prefix:-no}" != "no"])
+
+# Control over what links are made for installed files.  Versioned files are
+# always installed, when the following options are turned on corresponding
+# unversioned links are also created (normally as symbolic links):
+AC_ARG_ENABLE([unversioned-links],
+   AS_HELP_STRING([[[--enable-unversioned-links]]],
+      [Installed libpng header files are placed in a versioned subdirectory]
+      [and installed libpng library (including DLL) files are versioned.]
+      [If this option is enabled unversioned links will be created pointing to]
+      [the corresponding installed files.  If you use libpng.pc or]
+      [libpng-config for all builds you do not need these links, but if you]
+      [compile programs directly they will typically #include <png.h> and]
+      [link with -lpng; in that case you need the links.]
+      [The links can be installed manually using 'make install-header-links']
+      [and 'make install-library-links' and can be removed using the]
+      [corresponding uninstall- targets.  If you do enable this option every]
+      [libpng 'make install' will recreate the links to point to the just]
+      [installed version of libpng.  The default is to create the links;]
+      [use --disable-unversioned-links to change this]))
+
+# The AM_CONDITIONAL test is written so that the default is enabled;
+# --disable-unversioned-links must be given to turn the option off.
+AM_CONDITIONAL([DO_INSTALL_LINKS],[test "$enable_unversioned_links" != "no"])
+
+AC_ARG_ENABLE([unversioned-libpng-pc],
+   AS_HELP_STRING([[[--enable-unversioned-libpng-pc]]],
+      [Install the configuration file 'libpng.pc' as a link to the versioned]
+      [version.  This is done by default - use --disable-unversioned-libpng-pc]
+      [to change this.]))
+AM_CONDITIONAL([DO_INSTALL_LIBPNG_PC],
+   [test "$enable_unversioned_libpng_pc" != "no"])
+
+AC_ARG_ENABLE([unversioned-libpng-config],
+   AS_HELP_STRING([[[--enable-unversioned-libpng-config]]],
+      [Install the configuration file 'libpng-config' as a link to the]
+      [versioned version.  This is done by default - use]
+      [--disable-unversioned-libpng-config to change this.]))
+AM_CONDITIONAL([DO_INSTALL_LIBPNG_CONFIG],
+   [test "$enable_unversioned_libpng_config" != "no"])
+
+# HOST SPECIFIC OPTIONS
+# =====================
+#
+# ARM
+# ===
+#
+# ARM NEON (SIMD) support.

 AC_ARG_ENABLE([arm-neon],
-	AC_HELP_STRING([--enable-arm-neon], [Enable ARM NEON optimizations]),
-	[if test "${enableval}" = yes; then
-		AC_DEFINE([PNG_ARM_NEON], [1], [Enable ARM NEON optimizations])
-		AC_DEFINE([PNG_ALIGNED_MEMORY_SUPPORTED], [1], [Align row buffers])
-	fi])
-AM_CONDITIONAL([PNG_ARM_NEON], [test "${enable_arm_neon:-no}" = yes])
+   AS_HELP_STRING([[[--enable-arm-neon]]],
+      [Enable ARM NEON optimizations: =no/off, check, api, yes/on:]
+      [no/off: disable the optimizations; check: use internal checking code]
+      [(deprecated and poorly supported); api: disable by default, enable by]
+      [a call to png_set_option; yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __ARM_NEON__ systems:
+         AC_DEFINE([PNG_ARM_NEON_OPT], [0],
+                   [Disable ARM Neon optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_arm_neon=no;;
+      check)
+         AC_DEFINE([PNG_ARM_NEON_CHECK_SUPPORTED], [],
+                   [Check for ARM Neon support at run-time]);;
+      api)
+         AC_DEFINE([PNG_ARM_NEON_API_SUPPORTED], [],
+                   [Turn on ARM Neon optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_ARM_NEON_OPT], [2],
+                   [Enable ARM Neon optimizations])
+         AC_MSG_WARN([--enable-arm-neon: please specify 'check' or 'api', if]
+            [you want the optimizations unconditionally pass -mfpu=neon]
+            [to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-arm-neon=${enable_arm_neon}: invalid value])
+   esac])
+
+# Add ARM specific files to all builds where the host_cpu is arm ('arm*') or
+# where ARM optimizations were explicitly requested (this allows a fallback if a
+# future host CPU does not match 'arm*')
+
+AM_CONDITIONAL([PNG_ARM_NEON],
+   [test "$enable_arm_neon" != 'no' &&
+    case "$host_cpu" in
+      arm*|aarch64*) :;;
+      *)    test "$enable_arm_neon" != '';;
+    esac])
+
+AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])

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

 AC_OUTPUT
--- a/contrib/arm-neon/README
+++ b/contrib/arm-neon/README
@@ -0,0 +1,83 @@
+OPERATING SYSTEM SPECIFIC ARM NEON DETECTION
+--------------------------------------------
+
+Detection of the ability to execute ARM NEON on an ARM processor requires
+operating system support.  (The information is not available in user mode.)
+
+HOW TO USE THIS
+---------------
+
+This directory contains C code fragments that can be included in arm/arm_init.c
+by setting the macro PNG_ARM_NEON_FILE to the file name in "" or <> at build
+time.  This setting is not recorded in pnglibconf.h and can be changed simply by
+rebuilding arm/arm_init.o with the required macro definition.
+
+For any of this code to be used the ARM NEON code must be enabled and run time
+checks must be supported.  I.e.:
+
+#if PNG_ARM_NEON_OPT > 0
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-arm-neon=check
+
+Apart from the basic Linux implementation in contrib/arm-neon/linux.c this code
+is unsupported.  That means that it is not even compiled on a regular basis and
+may be broken in any given minor release.
+
+FILE FORMAT
+-----------
+
+Each file documents its testing status as of the last time it was tested (which
+may have been a long time ago):
+
+STATUS: one of:
+   SUPPORTED: This indicates that the file is included in the regularly
+         performed test builds and bugs are fixed when discovered.
+   COMPILED: This indicates that the code did compile at least once.  See the
+         more detailed description for the extent to which the result was
+         successful.
+   TESTED: This means the code was fully compiled into the libpng test programs
+         and these were run at least once.
+
+BUG REPORTS: an email address to which to send reports of problems
+
+The file is a fragment of C code. It should not define any 'extern' symbols;
+everything should be static.  It must define the function:
+
+static int png_have_neon(png_structp png_ptr);
+
+That function must return 1 if ARM NEON instructions are supported, 0 if not.
+It must not execute png_error unless it detects a bug.  A png_error will prevent
+the reading of the PNG and in the future, writing too.
+
+BUG REPORTS
+-----------
+
+If you mail a bug report for any file that is not SUPPORTED there may only be
+limited response.  Consider fixing it and sending a patch to fix the problem -
+this is more likely to result in action.
+
+CONTRIBUTIONS
+-------------
+
+You may send contributions of new implementations to
+png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+possible.  Obviously OS dependencies are to be expected.  If you submit code you
+must have the authors permission and it must have a license that is acceptable
+to the current maintainer; in particular that license must permit modification
+and redistribution.
+
+Please try to make the contribution a single file and give the file a clear and
+unambiguous name that identifies the target OS.  If multiple files really are
+required put them all in a sub-directory.
+
+You must also be prepared to handle bug reports from users of the code, either
+by joining the png-mng-implement mailing list or by providing an email for the
+"BUG REPORTS" entry or both.  Please make sure that the header of the file
+contains the STATUS and BUG REPORTS fields as above.
+
+Please list the OS requirements as precisely as possible.  Ideally you should
+also list the environment in which the code has been tested and certainly list
+any environments where you suspect it might not work.
--- a/contrib/arm-neon/android-ndk.c
+++ b/contrib/arm-neon/android-ndk.c
@@ -0,0 +1,39 @@
+/* contrib/arm-neon/android-ndk.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by John Bowler, 2014.
+ * Last changed in libpng 1.6.10 [March 6, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: COMPILED, UNTESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for the Android NDK, see:
+ *
+ * Documentation:
+ *    http://www.kandroid.org/ndk/docs/CPU-ARM-NEON.html
+ *    http://code.google.com/p/android/issues/detail?id=49065
+ *
+ * NOTE: this requires that libpng is built against the Android NDK and linked
+ * with an implementation of the Android ARM 'cpu-features' library.  The code
+ * has been compiled only, not linked: no version of the library has been found,
+ * only the header files exist in the NDK.
+ */
+#include <cpu-features.h>
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   /* This is a whole lot easier than the linux code, however it is probably
+    * implemented as below, therefore it is better to cache the result (these
+    * function calls may be slow!)
+    */
+   PNG_UNUSED(png_ptr)
+   return android_getCpuFamily() == ANDROID_CPU_FAMILY_ARM &&
+      (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) != 0;
+}
--- a/contrib/arm-neon/linux-auxv.c
+++ b/contrib/arm-neon/linux-auxv.c
@@ -0,0 +1,120 @@
+/* contrib/arm-neon/linux-auxv.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ * Last changed in libpng 1.6.10 [March 6, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ * 
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: COMPILED, TESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for Linux versions which allow access to
+ * /proc/self/auxv.  This is probably faster, cleaner and safer than the code to
+ * read /proc/cpuinfo in contrib/arm-neon/linux, however it is yet another piece
+ * of potentially untested code and has more complex dependencies than the code
+ * to read cpuinfo.
+ *
+ * This generic __linux__ implementation requires reading /proc/self/auxv and
+ * looking at each element for one that records NEON capabilities.
+ */
+#include <unistd.h> /* for POSIX 1003.1 */
+#include <errno.h>  /* for EINTR */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <elf.h>
+#include <asm/hwcap.h>
+
+/* A read call may be interrupted, in which case it returns -1 and sets errno to
+ * EINTR if nothing was done, otherwise (if something was done) a partial read
+ * may result.
+ */
+static size_t
+safe_read(png_structp png_ptr, int fd, void *buffer_in, size_t nbytes)
+{
+   size_t ntotal = 0;
+   char *buffer = png_voidcast(char*, buffer_in);
+
+   while (nbytes > 0)
+   {
+      unsigned int nread;
+      int iread;
+
+      /* Passing nread > INT_MAX to read is implementation defined in POSIX
+       * 1003.1, therefore despite the unsigned argument portable code must
+       * limit the value to INT_MAX!
+       */
+      if (nbytes > INT_MAX)
+         nread = INT_MAX;
+
+      else
+         nread = (unsigned int)/*SAFE*/nbytes;
+
+      iread = read(fd, buffer, nread);
+
+      if (iread == -1)
+      {
+         /* This is the devil in the details, a read can terminate early with 0
+          * bytes read because of EINTR, yet it still returns -1 otherwise end
+          * of file cannot be distinguished.
+          */
+         if (errno != EINTR)
+         {
+            png_warning(png_ptr, "/proc read failed");
+            return 0; /* I.e., a permanent failure */
+         }
+      }
+
+      else if (iread < 0)
+      {
+         /* Not a valid 'read' result: */
+         png_warning(png_ptr, "OS /proc read bug");
+         return 0;
+      }
+
+      else if (iread > 0)
+      {
+         /* Continue reading until a permanent failure, or EOF */
+         buffer += iread;
+         nbytes -= (unsigned int)/*SAFE*/iread;
+         ntotal += (unsigned int)/*SAFE*/iread;
+      }
+
+      else
+         return ntotal;
+   }
+
+   return ntotal; /* nbytes == 0 */
+}
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   int fd = open("/proc/self/auxv", O_RDONLY);
+   Elf32_auxv_t aux;
+
+   /* Failsafe: failure to open means no NEON */
+   if (fd == -1)
+   {
+      png_warning(png_ptr, "/proc/self/auxv open failed");
+      return 0;
+   }
+
+   while (safe_read(png_ptr, fd, &aux, sizeof aux) == sizeof aux)
+   {
+      if (aux.a_type == AT_HWCAP && (aux.a_un.a_val & HWCAP_NEON) != 0)
+      {
+         close(fd);
+         return 1;
+      }
+   }
+
+   close(fd);
+   return 0;
+}
--- a/contrib/arm-neon/linux.c
+++ b/contrib/arm-neon/linux.c
@@ -0,0 +1,161 @@
+/* contrib/arm-neon/linux.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by John Bowler, 2014.
+ * Last changed in libpng 1.6.16 [December 22, 2014]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: SUPPORTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for Linux by reading the widely available
+ * pseudo-file /proc/cpuinfo.
+ *
+ * This code is strict ANSI-C and is probably moderately portable; it does
+ * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ */
+#include <stdio.h>
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   FILE *f = fopen("/proc/cpuinfo", "rb");
+
+   if (f != NULL)
+   {
+      /* This is a simple state machine which reads the input byte-by-byte until
+       * it gets a match on the 'neon' feature or reaches the end of the stream.
+       */
+      static const char ch_feature[] = { 70, 69, 65, 84, 85, 82, 69, 83 };
+      static const char ch_neon[] = { 78, 69, 79, 78 };
+
+      enum
+      {
+         StartLine, Feature, Colon, StartTag, Neon, HaveNeon, SkipTag, SkipLine
+      }  state;
+      int counter;
+
+      for (state=StartLine, counter=0;;)
+      {
+         int ch = fgetc(f);
+
+         if (ch == EOF)
+         {
+            /* EOF means error or end-of-file, return false; neon at EOF is
+             * assumed to be a mistake.
+             */
+            fclose(f);
+            return 0;
+         }
+
+         switch (state)
+         {
+            case StartLine:
+               /* Match spaces at the start of line */
+               if (ch <= 32) /* skip control characters and space */
+                  break;
+
+               counter=0;
+               state = Feature;
+               /* FALL THROUGH */
+
+            case Feature:
+               /* Match 'FEATURE', ASCII case insensitive. */
+               if ((ch & ~0x20) == ch_feature[counter])
+               {
+                  if (++counter == (sizeof ch_feature))
+                     state = Colon;
+                  break;
+               }
+               
+               /* did not match 'feature' */
+               state = SkipLine;
+               /* FALL THROUGH */
+
+            case SkipLine:
+            skipLine:
+               /* Skip everything until we see linefeed or carriage return */
+               if (ch != 10 && ch != 13)
+                  break;
+
+               state = StartLine;
+               break;
+
+            case Colon:
+               /* Match any number of space or tab followed by ':' */
+               if (ch == 32 || ch == 9)
+                  break;
+
+               if (ch == 58) /* i.e. ':' */
+               {
+                  state = StartTag;
+                  break;
+               }
+
+               /* Either a bad line format or a 'feature' prefix followed by
+                * other characters.
+                */
+               state = SkipLine;
+               goto skipLine;
+
+            case StartTag:
+               /* Skip space characters before a tag */
+               if (ch == 32 || ch == 9)
+                  break;
+
+               state = Neon;
+               counter = 0;
+               /* FALL THROUGH */
+
+            case Neon:
+               /* Look for 'neon' tag */
+               if ((ch & ~0x20) == ch_neon[counter])
+               {
+                  if (++counter == (sizeof ch_neon))
+                     state = HaveNeon;
+                  break;
+               }
+
+               state = SkipTag;
+               /* FALL THROUGH */
+
+            case SkipTag:
+               /* Skip non-space characters */
+               if (ch == 10 || ch == 13)
+                  state = StartLine;
+
+               else if (ch == 32 || ch == 9)
+                  state = StartTag;
+               break;
+
+            case HaveNeon:
+               /* Have seen a 'neon' prefix, but there must be a space or new
+                * line character to terminate it.
+                */
+               if (ch == 10 || ch == 13 || ch == 32 || ch == 9)
+               {
+                  fclose(f);
+                  return 1;
+               }
+
+               state = SkipTag;
+               break;
+
+            default:
+               png_error(png_ptr, "png_have_neon: internal error (bug)");
+         }
+      }
+   }
+
+#ifdef PNG_WARNINGS_SUPPORTED
+   else
+      png_warning(png_ptr, "/proc/cpuinfo open failed");
+#endif
+
+   return 0;
+}
--- a/contrib/conftest/README
+++ b/contrib/conftest/README
@@ -0,0 +1,49 @@
+This directory contains test configuration files, currently always '.dfa' files
+intended to be used in the build by setting the make macro DFA_XTRA to the name
+of the file.
+
+These files are used in release validation of the 'configure' builds of libpng
+by building 'make check', or 'make all-am' for cross-builds, with each .dfa
+file.
+
+The files in this directory may change between minor releases, however
+contributions describing specific builds of libpng are welcomed.  There is no
+guarantee that libpng will continue to build with such configurations; support
+for given configurations can be, and has been, dropped between successive minor
+releases.  However if a .dfa file describing a configuration is not in this
+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
+=============
+
+Examples:
+   ${srcdir}/pngusr.dfa
+   ${srcdir}/contrib/pngminim/*/pngusr.dfa
+
+Documentation of the options:
+   ${srcdir}/scripts/pnglibconf.dfa
+
+Documentation of the file format:
+   ${srcdir}/scripts/options.awk
+
+FILE NAMING
+===========
+
+File names in this directory may NOT contain any of the five characters:
+
+   - , + * ?
+
+Neither may they contain any space character.
+
+While other characters may be used it is strongly suggested that file names be
+limited to lower case Latiin alphabetic characters (a-z), digits (0-9) and, if
+necessary the underscore (_) character.  File names should be about 8 characters
+long (excluding the .dfa extension).  Submitted .dfa files should have names
+between 7 and 16 characters long, shorter names (6 characters or less) are
+reserved for standard tests.
--- a/contrib/conftest/read.dfa
+++ b/contrib/conftest/read.dfa
@@ -0,0 +1,58 @@
+# read.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  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.
+#
+# Build libpng with basic read support.  This enables the lowest level libpng
+# read API - the one where the calling code has to use a loop to read each row.
+# At present this is the API used by most programs.
+#
+# Support is enabled only for those chunks and transformations that are
+# typically required - others can be added easily.
+#
+
+everything = off
+
+# The sequential read code is enabled here; the progressive code can be used
+# instead but there is no point enabling both.
+
+option SEQUENTIAL_READ on
+
+# Likewise it is pointless enabling both fixed and floating point APIs.  Choose
+# one or the other for both the API and the internal math.
+
+#Fixed point:
+#option FIXED_POINT on
+#option FLOATING_ARITHMETIC off
+
+#Floating point:
+option FLOATING_POINT on
+option FLOATING_ARITHMETIC on
+
+# Basic error handling, IO and user memory support.  The latter allows the
+# application program to provide its own implementations of 'malloc' and 'free'.
+option SETJMP on
+option STDIO on
+option USER_MEM on
+
+# To read the full set of PNG images correctly interlace, transparency and
+# 16-bit support is required.  The application can implement interlace itself,
+# but very few do and it's no longer possible to disable it when READ is
+# enabled.
+option READ_tRNS on
+option READ_16BIT on
+
+# Everything else is application dependent.  This file assumes the app handles
+# all the native PNG bit layouts, so it doesn't need any of layout change
+# transforms, but needs libpng to perform gamma correction.  It doesn't do any
+# colorspace stuff and ignores the 'significant bit' information.
+#
+# If your app always expands the image to a limited set of bit layouts you
+# probably want to consider using the simplified API instead of the low level
+# one - see png.h and s_read.dfa.
+option READ_GAMMA on
--- a/contrib/conftest/s_read.dfa
+++ b/contrib/conftest/s_read.dfa
@@ -0,0 +1,35 @@
+# s_read.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  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.
+#
+# Build libpng with simplified read support (only).  This builds a minimal
+# libpng able to read all PNG formats and convert them into a small number of
+# well understood memory formats.
+#
+
+everything = off
+
+option SIMPLIFIED_READ on
+
+# It isn't necessary to chose fixed or floating point for the APIs because the
+# simplified API doesn't need fixed or floating point numbers.  It is necessary
+# to chose an internal math implementation.  The default (because of 'everything
+# = off') is fixed point - turn the floating point implementation on if you have
+# hardware floating point or prefer your software floating point implementation.
+option FLOATING_ARITHMETIC on
+
+# This is not strictly necessary, but without it the message strings in the API
+# will not be filled in
+option ERROR_TEXT on
+
+# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
+# need this if you don't use them, they just allow the in-memory layout to be
+# changed to match common hardware formats.
+option SIMPLIFIED_READ_AFIRST on
+option SIMPLIFIED_READ_BGR on
--- a/contrib/conftest/s_write.dfa
+++ b/contrib/conftest/s_write.dfa
@@ -0,0 +1,33 @@
+# s_write.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  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.
+#
+# Build libpng with (just) simplified write support
+#
+
+everything = off
+
+option SIMPLIFIED_WRITE on
+
+# It isn't necessary to chose fixed or floating point for the APIs because the
+# simplified API doesn't need fixed or floating point numbers.  It is necessary
+# to chose an internal math implementation.  The default (because of 'everything
+# = off') is fixed point - turn the floating point implementation on if you have
+# hardware floating point or prefer your software floating point implementation.
+option FLOATING_ARITHMETIC on
+
+# This is not strictly necessary, but without it the message strings in the API
+# will not be filled in
+option ERROR_TEXT on
+
+# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
+# need this if you don't use them, they just allow the in-memory layout to be
+# changed to match common hardware formats.
+option SIMPLIFIED_WRITE_AFIRST on
+option SIMPLIFIED_WRITE_BGR on
--- a/contrib/conftest/simple.dfa
+++ b/contrib/conftest/simple.dfa
@@ -0,0 +1,36 @@
+# simple.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  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.
+#
+# Build libpng with just the simplified APIs (read and write).
+#
+
+everything = off
+
+option SIMPLIFIED_WRITE on
+option SIMPLIFIED_READ on
+
+# It isn't necessary to chose fixed or floating point for the APIs because the
+# simplified API doesn't need fixed or floating point numbers.  It is necessary
+# to chose an internal math implementation.  The default (because of 'everything
+# = off') is fixed point - turn the floating point implementation on if you have
+# hardware floating point or prefer your software floating point implementation.
+option FLOATING_ARITHMETIC on
+
+# This is not strictly necessary, but without it the message strings in the API
+# will not be filled in
+option ERROR_TEXT on
+
+# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
+# need this if you don't use them, they just allow the in-memory layout to be
+# changed to match common hardware formats.
+option SIMPLIFIED_READ_AFIRST on
+option SIMPLIFIED_READ_BGR on
+option SIMPLIFIED_WRITE_AFIRST on
+option SIMPLIFIED_WRITE_BGR on
--- a/contrib/conftest/write.dfa
+++ b/contrib/conftest/write.dfa
@@ -0,0 +1,45 @@
+# write.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  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.
+#
+# Build libpng with no read support and minimal write support.
+#
+
+everything = off
+
+# Switch on the write code - this makes a minimalist encoder
+
+option WRITE on
+
+# Choose fixed or floating point APIs and arithmetic.  The choices are
+# independent but normally they will match.  It is typically better to use the
+# floating point if you have floating point hardware.  If you don't know, or
+# (perhaps) to make libpng smaller used fixed point throughout.
+
+#Fixed point:
+#option FIXED_POINT on
+#option FLOATING_ARITHMETIC off
+
+#Floating point:
+option FLOATING_POINT on
+option FLOATING_ARITHMETIC on
+
+# Basic error handling, IO and user memory support.  The latter allows the
+# application program to provide its own implementations of 'malloc' and 'free'.
+option SETJMP on
+option STDIO on
+option USER_MEM on
+
+# Everything else is optional.  Unlike the read code in libpng the write code
+# does not need to deal with arbitrary formats, so only add support for things
+# you really do write!  For example you might only write sRGB images, sometimes
+# with transparency and never write 16 bit images, so:
+option WRITE_sRGB on
+option WRITE_tRNS on
+#option WRITE_16BIT off (this is the default with 'everything = off')
--- a/contrib/examples/README.txt
+++ b/contrib/examples/README.txt
@@ -0,0 +1,24 @@
+
+This directory (contrib/examples) contains examples of libpng usage.
+
+NO COPYRIGHT RIGHTS ARE CLAIMED TO ANY OF THE FILES IN THIS DIRECTORY.
+
+To the extent possible under law, the authors have waived all copyright and
+related or neighboring rights to this work.  This work is published from:
+United States.
+
+The files may be used freely in any way.  The intention is that appropriate
+parts of the files be used in other libpng-using programs without any need for
+the authors of the using code to seek copyright or license from the original
+authors.
+
+The source code and comments in this directory are the original work of the
+people named below.  No other person or organization has made contributions to
+the work in this directory.
+
+ORIGINAL AUTHORS
+    The following people have contributed to the code in this directory.  None
+    of the people below claim any rights with regard to the contents of this
+    directory.
+
+    John Bowler <jbowler@acm.org>
--- a/contrib/examples/iccfrompng.c
+++ b/contrib/examples/iccfrompng.c
@@ -0,0 +1,185 @@
+/*- iccfrompng
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011.
+ * 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.
+ *
+ * Extract any icc profiles found in the given PNG files.  This is a simple
+ * example of a program that extracts information from the header of a PNG file
+ * without processing the image.  Notice that some header information may occur
+ * after the image data. Textual data and comments are an example; the approach
+ * in this file won't work reliably for such data because it only looks for the
+ * information in the section of the file that preceeds the image data.
+ *
+ * Compile and link against libpng and zlib, plus anything else required on the
+ * system you use.
+ *
+ * To use supply a list of PNG files containing iCCP chunks, the chunks will be
+ * extracted to a similarly named file with the extension replaced by 'icc',
+ * which will be overwritten without warning.
+ */
+#include <stdlib.h>
+#include <setjmp.h>
+#include <string.h>
+#include <stdio.h>
+
+#include <png.h>
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \
+    defined (PNG_iCCP_SUPPORTED)
+
+
+static int verbose = 1;
+static png_byte no_profile[] = "no profile";
+
+static png_bytep
+extract(FILE *fp, png_uint_32 *proflen)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
+   png_infop info_ptr = NULL;
+   png_bytep result = NULL;
+
+   /* Initialize for error or no profile: */
+   *proflen = 0;
+
+   if (png_ptr == NULL)
+   {
+      fprintf(stderr, "iccfrompng: version library mismatch?\n");
+      return 0;
+   }
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      return 0;
+   }
+
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   png_read_info(png_ptr, info_ptr);
+
+   {
+      png_charp name;
+      int compression_type;
+      png_bytep profile;
+
+      if (png_get_iCCP(png_ptr, info_ptr, &name, &compression_type, &profile,
+         proflen) & PNG_INFO_iCCP)
+      {
+         result = malloc(*proflen);
+         if (result != NULL)
+            memcpy(result, profile, *proflen);
+
+         else
+            png_error(png_ptr, "OOM allocating profile buffer");
+      }
+
+      else
+	result = no_profile;
+   }
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   return result;
+}
+
+static int
+extract_one_file(const char *filename)
+{
+   int result = 0;
+   FILE *fp = fopen(filename, "rb");
+
+   if (fp != NULL)
+   {
+      png_uint_32 proflen = 0;
+      png_bytep profile = extract(fp, &proflen);
+
+      if (profile != NULL && profile != no_profile)
+      {
+         size_t len;
+         char *output;
+
+         {
+            const char *ep = strrchr(filename, '.');
+
+            if (ep != NULL)
+               len = ep-filename;
+
+            else
+               len = strlen(filename);
+         }
+
+         output = malloc(len + 5);
+         if (output != NULL)
+         {
+            FILE *of;
+
+            memcpy(output, filename, len);
+            strcpy(output+len, ".icc");
+
+            of = fopen(output, "wb");
+            if (of != NULL)
+            {
+               if (fwrite(profile, proflen, 1, of) == 1 &&
+                  fflush(of) == 0 &&
+                  fclose(of) == 0)
+               {
+                  if (verbose)
+                     printf("%s -> %s\n", filename, output);
+                  /* Success return */
+                  result = 1;
+               }
+
+               else
+               {
+                  fprintf(stderr, "%s: error writing profile\n", output);
+                  if (remove(output))
+                     fprintf(stderr, "%s: could not remove file\n", output);
+               }
+            }
+
+            else
+               fprintf(stderr, "%s: failed to open output file\n", output);
+
+            free(output);
+         }
+
+         else
+            fprintf(stderr, "%s: OOM allocating string!\n", filename);
+
+         free(profile);
+      }
+
+      else if (verbose && profile == no_profile)
+	printf("%s has no profile\n", filename);
+   }
+
+   else
+      fprintf(stderr, "%s: could not open file\n", filename);
+
+   return result;
+}
+
+int
+main(int argc, char **argv)
+{
+   int i;
+   int extracted = 0;
+
+   for (i=1; i<argc; ++i)
+   {
+      if (strcmp(argv[i], "-q") == 0)
+         verbose = 0;
+
+      else if (extract_one_file(argv[i]))
+         extracted = 1;
+   }
+
+   /* Exit code is true if any extract succeeds */
+   return extracted == 0;
+}
+#endif /* READ && STDIO && iCCP */
--- a/contrib/examples/pngpixel.c
+++ b/contrib/examples/pngpixel.c
@@ -0,0 +1,371 @@
+/*- pngpixel
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011.
+ * 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.
+ *
+ * Read a single pixel value from a PNG file.
+ *
+ * This code illustrates basic 'by-row' reading of a PNG file using libpng.
+ * Rows are read until a particular pixel is found; the value of this pixel is
+ * then printed on stdout.
+ *
+ * The code illustrates how to do this on interlaced as well as non-interlaced
+ * images.  Normally you would call png_set_interlace_handling() to have libpng
+ * deal with the interlace for you, but that obliges you to buffer half of the
+ * image to assemble the interlaced rows.  In this code
+ * png_set_interlace_handling() is not called and, instead, the code handles the
+ * interlace passes directly looking for the required pixel.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <setjmp.h> /* required for error handling */
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation:
+ */
+#include "../../png.h"
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+
+/* Return component 'c' of pixel 'x' from the given row. */
+static unsigned int
+component(png_const_bytep row, png_uint_32 x, unsigned int c,
+   unsigned int bit_depth, unsigned int channels)
+{
+   /* PNG images can be up to 2^31 pixels wide, but this means they can be up to
+    * 2^37 bits wide (for a 64-bit pixel - the largest possible) and hence 2^34
+    * bytes wide.  Since the row fitted into memory, however, the following must
+    * work:
+    */
+   png_uint_32 bit_offset_hi = bit_depth * ((x >> 6) * channels);
+   png_uint_32 bit_offset_lo = bit_depth * ((x & 0x3f) * channels + c);
+
+   row = (png_const_bytep)(((PNG_CONST png_byte (*)[8])row) + bit_offset_hi);
+   row += bit_offset_lo >> 3;
+   bit_offset_lo &= 0x07;
+
+   /* PNG pixels are packed into bytes to put the first pixel in the highest
+    * bits of the byte and into two bytes for 16-bit values with the high 8 bits
+    * first, so:
+    */
+   switch (bit_depth)
+   {
+      case 1: return (row[0] >> (7-bit_offset_lo)) & 0x01;
+      case 2: return (row[0] >> (6-bit_offset_lo)) & 0x03;
+      case 4: return (row[0] >> (4-bit_offset_lo)) & 0x0f;
+      case 8: return row[0];
+      case 16: return (row[0] << 8) + row[1];
+      default:
+         /* This should never happen; it indicates a bug in this program or in
+          * libpng itself:
+          */
+         fprintf(stderr, "pngpixel: invalid bit depth %u\n", bit_depth);
+         exit(1);
+   }
+}
+
+/* Print a pixel from a row returned by libpng; determine the row format, find
+ * the pixel, and print the relevant information to stdout.
+ */
+static void
+print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
+   png_uint_32 x)
+{
+   PNG_CONST unsigned int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
+
+   switch (png_get_color_type(png_ptr, info_ptr))
+   {
+      case PNG_COLOR_TYPE_GRAY:
+         printf("GRAY %u\n", component(row, x, 0, bit_depth, 1));
+         return;
+
+      /* The palette case is slightly more difficult - the palette and, if
+       * present, the tRNS ('transparency', though the values are really
+       * opacity) data must be read to give the full picture:
+       */
+      case PNG_COLOR_TYPE_PALETTE:
+         {
+            PNG_CONST unsigned int index = component(row, x, 0, bit_depth, 1);
+            png_colorp palette = NULL;
+            int num_palette = 0;
+
+            if ((png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) &
+               PNG_INFO_PLTE) && num_palette > 0 && palette != NULL)
+            {
+               png_bytep trans_alpha = NULL;
+               int num_trans = 0;
+               if ((png_get_tRNS(png_ptr, info_ptr, &trans_alpha, &num_trans,
+                  NULL) & PNG_INFO_tRNS) && num_trans > 0 &&
+                  trans_alpha != NULL)
+                  printf("INDEXED %u = %d %d %d %d\n", index,
+                     palette[index].red, palette[index].green,
+                     palette[index].blue,
+                     index < num_trans ? trans_alpha[index] : 255);
+
+               else /* no transparency */
+                  printf("INDEXED %u = %d %d %d\n", index,
+                     palette[index].red, palette[index].green,
+                     palette[index].blue);
+            }
+
+            else
+               printf("INDEXED %u = invalid index\n", index);
+         }
+         return;
+
+      case PNG_COLOR_TYPE_RGB:
+         printf("RGB %u %u %u\n", component(row, x, 0, bit_depth, 3),
+            component(row, x, 1, bit_depth, 3),
+            component(row, x, 2, bit_depth, 3));
+         return;
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         printf("GRAY+ALPHA %u %u\n", component(row, x, 0, bit_depth, 2),
+            component(row, x, 1, bit_depth, 2));
+         return;
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         printf("RGBA %u %u %u %u\n", component(row, x, 0, bit_depth, 4),
+            component(row, x, 1, bit_depth, 4),
+            component(row, x, 2, bit_depth, 4),
+            component(row, x, 3, bit_depth, 4));
+         return;
+
+      default:
+         png_error(png_ptr, "pngpixel: invalid color type");
+   }
+}
+
+int main(int argc, const char **argv)
+{
+   /* This program uses the default, <setjmp.h> based, libpng error handling
+    * mechanism, therefore any local variable that exists before the call to
+    * setjmp and is changed after the call to setjmp returns successfully must
+    * be declared with 'volatile' to ensure that their values don't get
+    * destroyed by longjmp:
+    */
+   volatile int result = 1/*fail*/;
+
+   if (argc == 4)
+   {
+      long x = atol(argv[1]);
+      long y = atol(argv[2]);
+      FILE *f = fopen(argv[3], "rb");
+      volatile png_bytep row = NULL;
+
+      if (f != NULL)
+      {
+         /* libpng requires a callback function for handling errors; this
+          * callback must not return.  The default callback function uses a
+          * stored <setjmp.h> style jmp_buf which is held in a png_struct and
+          * writes error messages to stderr.  Creating the png_struct is a
+          * little tricky; just copy the following code.
+          */
+         png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+            NULL, NULL, NULL);
+
+         if (png_ptr != NULL)
+         {
+            png_infop info_ptr = png_create_info_struct(png_ptr);
+
+            if (info_ptr != NULL)
+            {
+               /* Declare stack variables to hold pointers to locally allocated
+                * data.
+                */
+
+               /* Initialize the error control buffer: */
+               if (setjmp(png_jmpbuf(png_ptr)) == 0)
+               {
+                  png_uint_32 width, height;
+                  int bit_depth, color_type, interlace_method,
+                     compression_method, filter_method;
+                  png_bytep row_tmp;
+
+                  /* Now associate the recently opened (FILE*) with the default
+                   * libpng initialization functions.  Sometimes libpng is
+                   * compiled without stdio support (it can be difficult to do
+                   * in some environments); in that case you will have to write
+                   * your own read callback to read data from the (FILE*).
+                   */
+                  png_init_io(png_ptr, f);
+
+                  /* And read the first part of the PNG file - the header and
+                   * all the information up to the first pixel.
+                   */
+                  png_read_info(png_ptr, info_ptr);
+
+                  /* This fills in enough information to tell us the width of
+                   * each row in bytes, allocate the appropriate amount of
+                   * space.  In this case png_malloc is used - it will not
+                   * return if memory isn't available.
+                   */
+                  row = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
+                     info_ptr));
+
+                  /* To avoid the overhead of using a volatile auto copy row_tmp
+                   * to a local here - just use row for the png_free below.
+                   */
+                  row_tmp = row;
+
+                  /* All the information we need is in the header is returned by
+                   * png_get_IHDR, if this fails we can now use 'png_error' to
+                   * signal the error and return control to the setjmp above.
+                   */
+                  if (png_get_IHDR(png_ptr, info_ptr, &width, &height,
+                     &bit_depth, &color_type, &interlace_method,
+                     &compression_method, &filter_method))
+                  {
+                     int passes, pass;
+
+                     /* png_set_interlace_handling returns the number of
+                      * passes required as well as turning on libpng's
+                      * handling, but since we do it ourselves this is
+                      * necessary:
+                      */
+                     switch (interlace_method)
+                     {
+                        case PNG_INTERLACE_NONE:
+                           passes = 1;
+                           break;
+
+                        case PNG_INTERLACE_ADAM7:
+                           passes = PNG_INTERLACE_ADAM7_PASSES;
+                           break;
+
+                        default:
+                           png_error(png_ptr, "pngpixel: unknown interlace");
+                     }
+
+                     /* Now read the pixels, pass-by-pass, row-by-row: */
+                     png_start_read_image(png_ptr);
+
+                     for (pass=0; pass<passes; ++pass)
+                     {
+                        png_uint_32 ystart, xstart, ystep, xstep;
+                        png_uint_32 py;
+
+                        if (interlace_method == PNG_INTERLACE_ADAM7)
+                        {
+                           /* Sometimes the whole pass is empty because the
+                            * image is too narrow or too short.  libpng
+                            * expects to be called for each row that is
+                            * present in the pass, so it may be necessary to
+                            * skip the loop below (over py) if the image is
+                            * too narrow.
+                            */
+                           if (PNG_PASS_COLS(width, pass) == 0)
+                              continue;
+
+                           /* We need the starting pixel and the offset
+                            * between each pixel in this pass; use the macros
+                            * in png.h:
+                            */
+                           xstart = PNG_PASS_START_COL(pass);
+                           ystart = PNG_PASS_START_ROW(pass);
+                           xstep = PNG_PASS_COL_OFFSET(pass);
+                           ystep = PNG_PASS_ROW_OFFSET(pass);
+                        }
+
+                        else
+                        {
+                           ystart = xstart = 0;
+                           ystep = xstep = 1;
+                        }
+
+                        /* To find the pixel, loop over 'py' for each pass
+                         * reading a row and then checking to see if it
+                         * contains the pixel.
+                         */
+                        for (py = ystart; py < height; py += ystep)
+                        {
+                           png_uint_32 px, ppx;
+
+                           /* png_read_row takes two pointers.  When libpng
+                            * handles the interlace the first is filled in
+                            * pixel-by-pixel, and the second receives the same
+                            * pixels but they are replicated across the
+                            * unwritten pixels so far for each pass.  When we
+                            * do the interlace, however, they just contain
+                            * the pixels from the interlace pass - giving
+                            * both is wasteful and pointless, so we pass a
+                            * NULL pointer.
+                            */
+                           png_read_row(png_ptr, row_tmp, NULL);
+
+                           /* Now find the pixel if it is in this row; there
+                            * are, of course, much better ways of doing this
+                            * than using a for loop:
+                            */
+                           if (y == py) for (px = xstart, ppx = 0;
+                              px < width; px += xstep, ++ppx) if (x == px)
+                           {
+                              /* 'ppx' is the index of the pixel in the row
+                               * buffer.
+                               */
+                              print_pixel(png_ptr, info_ptr, row_tmp, ppx);
+
+                              /* Now terminate the loops early - we have
+                               * found and handled the required data.
+                               */
+                              goto pass_loop_end;
+                           } /* x loop */
+                        } /* y loop */
+                     } /* pass loop */
+
+                     /* Finally free the temporary buffer: */
+                  pass_loop_end:
+                     row = NULL;
+                     png_free(png_ptr, row_tmp);
+                  }
+
+                  else
+                     png_error(png_ptr, "pngpixel: png_get_IHDR failed");
+
+               }
+
+               else
+               {
+                  /* Else libpng has raised an error.  An error message has
+                   * already been output, so it is only necessary to clean up
+                   * locally allocated data:
+                   */
+                  if (row != NULL)
+                  {
+                     /* The default implementation of png_free never errors out
+                      * (it just crashes if something goes wrong), but the safe
+                      * way of using it is still to clear 'row' before calling
+                      * png_free:
+                      */
+                     png_bytep row_tmp = row;
+                     row = NULL;
+                     png_free(png_ptr, row_tmp);
+                  }
+               }
+
+               png_destroy_info_struct(png_ptr, &info_ptr);
+            }
+
+            else
+               fprintf(stderr, "pngpixel: out of memory allocating png_info\n");
+
+            png_destroy_read_struct(&png_ptr, NULL, NULL);
+         }
+
+         else
+            fprintf(stderr, "pngpixel: out of memory allocating png_struct\n");
+      }
+
+      else
+         fprintf(stderr, "pngpixel: %s: could not open file\n", argv[3]);
+   }
+
+   else
+      /* Wrong number of arguments */
+      fprintf(stderr, "pngpixel: usage: pngpixel x y png-file\n");
+
+   return result;
+}
+#endif /* READ && SEQUENTIAL_READ */
--- a/contrib/examples/pngtopng.c
+++ b/contrib/examples/pngtopng.c
@@ -0,0 +1,95 @@
+/*- pngtopng
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011.
+ * 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.
+ *
+ * Read a PNG and write it out in a fixed format, using the 'simplified API'
+ * that was introduced in libpng-1.6.0.
+ *
+ * This sample code is just the code from the top of 'example.c' with some error
+ * handling added.  See example.c for more comments.
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation:
+ */
+#include "../../png.h"
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && \
+    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+
+int main(int argc, const char **argv)
+{
+   int result = 1;
+
+   if (argc == 3)
+   {
+      png_image image;
+
+      /* Only the image structure version number needs to be set. */
+      memset(&image, 0, sizeof image);
+      image.version = PNG_IMAGE_VERSION;
+
+      if (png_image_begin_read_from_file(&image, argv[1]))
+      {
+         png_bytep buffer;
+
+         /* Change this to try different formats!  If you set a colormap format
+          * then you must also supply a colormap below.
+          */
+         image.format = PNG_FORMAT_RGBA;
+
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         if (buffer != NULL)
+         {
+            if (png_image_finish_read(&image, NULL/*background*/, buffer,
+               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
+            {
+               if (png_image_write_to_file(&image, argv[2],
+                  0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                  NULL/*colormap*/))
+                  result = 0;
+
+               else
+                  fprintf(stderr, "pngtopng: write %s: %s\n", argv[2],
+                      image.message);
+
+               free(buffer);
+            }
+
+            else
+            {
+               fprintf(stderr, "pngtopng: read %s: %s\n", argv[1],
+                   image.message);
+
+               /* This is the only place where a 'free' is required; libpng does
+                * the cleanup on error and success, but in this case we couldn't
+                * complete the read because of running out of memory.
+                */
+               png_image_free(&image);
+            }
+         }
+
+         else
+            fprintf(stderr, "pngtopng: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+      }
+
+      else
+         /* Failed to read the first argument: */
+         fprintf(stderr, "pngtopng: %s: %s\n", argv[1], image.message);
+   }
+
+   else
+      /* Wrong number of arguments */
+      fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n");
+
+   return result;
+}
+#endif /* READ && WRITE */
--- a/contrib/examples/simpleover.c
+++ b/contrib/examples/simpleover.c
@@ -0,0 +1,648 @@
+/*- simpleover
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2015.
+ * 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.
+ *
+ * Read several PNG files, which should have an alpha channel or transparency
+ * information, and composite them together to produce one or more 16-bit linear
+ * RGBA intermediates.  This involves doing the correct 'over' composition to
+ * combine the alpha channels and corresponding data.
+ *
+ * Finally read an output (background) PNG using the 24-bit RGB format (the
+ * PNG will be composited on green (#00ff00) by default if it has an alpha
+ * channel), and apply the intermediate image generated above to specified
+ * locations in the image.
+ *
+ * The command line has the general format:
+ *
+ *    simpleover <background.png> [output.png]
+ *        {--sprite=width,height,name {[--at=x,y] {sprite.png}}}
+ *        {--add=name {x,y}}
+ *
+ * The --sprite and --add options may occur multiple times. They are executed
+ * in order.  --add may refer to any sprite already read.
+ *
+ * This code is intended to show how to composite multiple images together
+ * correctly.  Apart from the libpng Simplified API the only work done in here
+ * is to combine multiple input PNG images into a single sprite; this involves
+ * a Porter-Duff 'over' operation and the input PNG images may, as a result,
+ * be regarded as being layered one on top of the other with the first (leftmost
+ * on the command line) being at the bottom and the last on the top.
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation, so long as this
+ * file is linked against a sufficiently recent libpng (1.6+) it is ok to
+ * change this to <png.h>:
+ */
+#include "../../png.h"
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+
+#define sprite_name_chars 15
+struct sprite {
+   FILE         *file;
+   png_uint_16p  buffer;
+   unsigned int  width;
+   unsigned int  height;
+   char          name[sprite_name_chars+1];
+};
+
+#if 0 /* div by 65535 test program */
+#include <math.h>
+#include <stdio.h>
+
+int main(void) {
+   double err = 0;
+   unsigned int xerr = 0;
+   unsigned int r = 32769;
+   {
+      unsigned int x = 0;
+
+      do {
+         unsigned int t = x + (x >> 16) /*+ (x >> 31)*/ + r;
+         double v = x, errtest;
+
+         if (t < x) {
+            fprintf(stderr, "overflow: %u+%u -> %u\n", x, r, t);
+            return 1;
+         }
+
+         v /= 65535;
+         errtest = v;
+         t >>= 16;
+         errtest -= t;
+
+         if (errtest > err) {
+            err = errtest;
+            xerr = x;
+
+            if (errtest >= .5) {
+               fprintf(stderr, "error: %u/65535 = %f, not %u, error %f\n",
+                     x, v, t, errtest);
+               return 0;
+            }
+         }
+      } while (++x <= 65535U*65535U);
+   }
+
+   printf("error %f @ %u\n", err, xerr);
+
+   return 0;
+}
+#endif /* div by 65535 test program */
+
+static void
+sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
+   png_imagep image, const png_uint_16 *buffer)
+{
+   /* This is where the Porter-Duff 'Over' operator is evaluated; change this
+    * code to change the operator (this could be parameterized).  Any other
+    * image processing operation could be used here.
+    */
+
+
+   /* Check for an x or y offset that pushes any part of the image beyond the
+    * right or bottom of the sprite:
+    */
+   if ((y_offset < 0 || (unsigned)/*SAFE*/y_offset < sprite->height) &&
+       (x_offset < 0 || (unsigned)/*SAFE*/x_offset < sprite->width))
+   {
+      unsigned int y = 0;
+
+      if (y_offset < 0)
+         y = -y_offset; /* Skip to first visible row */
+
+      do
+      {
+         unsigned int x = 0;
+
+         if (x_offset < 0)
+            x = -x_offset;
+
+         do
+         {
+            /* In and out are RGBA values, so: */
+            const png_uint_16 *in_pixel = buffer + (y * image->width + x)*4;
+            png_uint_32 in_alpha = in_pixel[3];
+
+            /* This is the optimized Porter-Duff 'Over' operation, when the
+             * input alpha is 0 the output is not changed.
+             */
+            if (in_alpha > 0) 
+            {
+               png_uint_16 *out_pixel = sprite->buffer +
+                  ((y+y_offset) * sprite->width + (x+x_offset))*4;
+
+               /* This is the weight to apply to the output: */
+               in_alpha = 65535-in_alpha;
+
+               if (in_alpha > 0)
+               {
+                  /* The input must be composed onto the output. This means
+                   * multiplying the current output pixel value by the inverse
+                   * of the input alpha (1-alpha). A division is required but
+                   * it is by the constant 65535.  Approximate this as:
+                   *
+                   *     (x + (x >> 16) + 32769) >> 16;
+                   *
+                   * This is exact (and does not overflow) for all values of
+                   * x in the range 0..65535*65535.  (Note that the calculation
+                   * produces the closest integer; the maximum error is <0.5).
+                   */
+                  png_uint_32 tmp;
+
+#                 define compose(c)\
+                     tmp = out_pixel[c] * in_alpha;\
+                     tmp = (tmp + (tmp >> 16) + 32769) >> 16;\
+                     out_pixel[c] = tmp + in_pixel[c]
+
+                  /* The following is very vectorizable... */
+                  compose(0);
+                  compose(1);
+                  compose(2);
+                  compose(3);
+               }
+
+               else
+                  out_pixel[0] = in_pixel[0],
+                  out_pixel[1] = in_pixel[1],
+                  out_pixel[2] = in_pixel[2],
+                  out_pixel[3] = in_pixel[3];
+            }
+         }
+         while (++x < image->width);
+      }
+      while (++y < image->height);
+   }
+}
+
+static int 
+create_sprite(struct sprite *sprite, int *argc, const char ***argv)
+{
+   /* Read the arguments and create this sprite. The sprite buffer has already
+    * been allocated. This reads the input PNGs one by one in linear format,
+    * composes them onto the sprite buffer (the code in the function above)
+    * then saves the result, converting it on the fly to PNG RGBA 8-bit format.
+    */
+   while (*argc > 0)
+   {
+      char tombstone;
+      int x = 0, y = 0;
+
+      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
+      {
+         /* The only supported option is --at. */
+         if (sscanf((*argv)[0], "--at=%d,%d%c", &x, &y, &tombstone) != 2)
+            break; /* success; caller will parse this option */
+
+         ++*argv, --*argc;
+      }
+
+      else
+      {
+         /* The argument has to be a file name */
+         png_image image;
+
+         image.version = PNG_IMAGE_VERSION;
+         image.opaque = NULL;
+
+         if (png_image_begin_read_from_file(&image, (*argv)[0]))
+         {
+            png_uint_16p buffer;
+
+            image.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+
+            buffer = malloc(PNG_IMAGE_SIZE(image));
+
+            if (buffer != NULL)
+            {
+               if (png_image_finish_read(&image, NULL/*background*/, buffer,
+                  0/*row_stride*/,
+                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+               {
+                  /* This is the place where the Porter-Duff 'Over' operator
+                   * needs to be done by this code.  In fact, any image
+                   * processing required can be done here; the data is in
+                   * the correct format (linear, 16-bit) and source and
+                   * destination are in memory.
+                   */
+                  sprite_op(sprite, x, y, &image, buffer);
+                  free(buffer);
+                  ++*argv, --*argc;
+                  /* And continue to the next argument */
+                  continue;
+               }
+
+               else
+               {
+                  free(buffer);
+                  fprintf(stderr, "simpleover: read %s: %s\n", (*argv)[0],
+                      image.message);
+               }
+            }
+
+            else
+            {
+               fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
+                  (unsigned long)PNG_IMAGE_SIZE(image));
+
+               /* png_image_free must be called if we abort the Simplified API
+                * read because of a problem detected in this code.  If problems
+                * are detected in the Simplified API it cleans up itself.
+                */
+               png_image_free(&image);
+            }
+         }
+
+         else
+         {
+            /* Failed to read the first argument: */
+            fprintf(stderr, "simpleover: %s: %s\n", (*argv)[0], image.message);
+         }
+
+         return 0; /* failure */
+      }
+   }
+
+   /* All the sprite operations have completed successfully. Save the RGBA
+    * buffer as a PNG using the simplified write API.
+    */
+   sprite->file = tmpfile();
+
+   if (sprite->file != NULL)
+   {
+      png_image save;
+
+      memset(&save, 0, sizeof save);
+      save.version = PNG_IMAGE_VERSION;
+      save.opaque = NULL;
+      save.width = sprite->width;
+      save.height = sprite->height;
+      save.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+      save.flags = PNG_IMAGE_FLAG_FAST;
+      save.colormap_entries = 0;
+
+      if (png_image_write_to_stdio(&save, sprite->file, 1/*convert_to_8_bit*/,
+          sprite->buffer, 0/*row_stride*/, NULL/*colormap*/))
+      {
+         /* Success; the buffer is no longer needed: */
+         free(sprite->buffer);
+         sprite->buffer = NULL;
+         return 1; /* ok */
+      }
+
+      else
+         fprintf(stderr, "simpleover: write sprite %s: %s\n", sprite->name,
+            save.message);
+   }
+
+   else
+      fprintf(stderr, "simpleover: sprite %s: could not allocate tmpfile: %s\n",
+         sprite->name, strerror(errno));
+
+   return 0; /* fail */
+}
+
+static int
+add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
+   int *argc, const char ***argv)
+{
+   /* Given a --add argument naming this sprite, perform the operations listed
+    * in the following arguments.  The arguments are expected to have the form
+    * (x,y), which is just an offset at which to add the sprite to the
+    * output.
+    */
+   while (*argc > 0)
+   {
+      char tombstone;
+      int x, y;
+
+      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
+         return 1; /* success */
+
+      if (sscanf((*argv)[0], "%d,%d%c", &x, &y, &tombstone) == 2)
+      {
+         /* Now add the new image into the sprite data, but only if it
+          * will fit.
+          */
+         if (x < 0 || y < 0 ||
+             (unsigned)/*SAFE*/x >= output->width ||
+             (unsigned)/*SAFE*/y >= output->height ||
+             sprite->width > output->width-x ||
+             sprite->height > output->height-y)
+         {
+            fprintf(stderr, "simpleover: sprite %s @ (%d,%d) outside image\n",
+               sprite->name, x, y);
+            /* Could just skip this, but for the moment it is an error */
+            return 0; /* error */
+         }
+
+         else
+         {
+            /* Since we know the sprite fits we can just read it into the
+             * output using the simplified API.
+             */
+            png_image in;
+
+            in.version = PNG_IMAGE_VERSION;
+            rewind(sprite->file);
+
+            if (png_image_begin_read_from_stdio(&in, sprite->file))
+            {
+               in.format = PNG_FORMAT_RGB; /* force compose */
+
+               if (png_image_finish_read(&in, NULL/*background*/,
+                  out_buf + (y*output->width + x)*3/*RGB*/,
+                  output->width*3/*row_stride*/,
+                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+               {
+                  ++*argv, --*argc;
+                  continue;
+               }
+            }
+
+            /* The read failed: */
+            fprintf(stderr, "simpleover: add sprite %s: %s\n", sprite->name,
+                in.message);
+            return 0; /* error */
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "simpleover: --add='%s': invalid position %s\n",
+               sprite->name, (*argv)[0]);
+         return 0; /* error */
+      }
+   }
+
+   return 1; /* ok */
+}
+
+static int
+simpleover_process(png_imagep output, png_bytep out_buf, int argc,
+   const char **argv)
+{
+   int result = 1; /* success */
+#  define csprites 10/*limit*/
+#  define str(a) #a
+   int nsprites = 0;
+   struct sprite sprites[csprites];
+
+   while (argc > 0)
+   {
+      result = 0; /* fail */
+
+      if (strncmp(argv[0], "--sprite=", 9) == 0)
+      {
+         char tombstone;
+
+         if (nsprites < csprites)
+         {
+            int n;
+
+            sprites[nsprites].width = sprites[nsprites].height = 0;
+            sprites[nsprites].name[0] = 0;
+
+            n = sscanf(argv[0], "--sprite=%u,%u,%" str(sprite_name_chars) "s%c",
+                &sprites[nsprites].width, &sprites[nsprites].height,
+                sprites[nsprites].name, &tombstone);
+            
+            if ((n == 2 || n == 3) &&
+                sprites[nsprites].width > 0 && sprites[nsprites].height > 0)
+            {
+               size_t buf_size, tmp;
+
+               /* Default a name if not given. */
+               if (sprites[nsprites].name[0] == 0)
+                  sprintf(sprites[nsprites].name, "sprite-%d", nsprites+1);
+
+               /* Allocate a buffer for the sprite and calculate the buffer
+                * size:
+                */
+               buf_size = sizeof (png_uint_16 [4]);
+               buf_size *= sprites[nsprites].width;
+               buf_size *= sprites[nsprites].height;
+
+               /* This can overflow a (size_t); check for this: */
+               tmp = buf_size;
+               tmp /= sprites[nsprites].width;
+               tmp /= sprites[nsprites].height;
+
+               if (tmp == sizeof (png_uint_16 [4]))
+               {
+                  sprites[nsprites].buffer = malloc(buf_size);
+                  /* This buffer must be initialized to transparent: */
+                  memset(sprites[nsprites].buffer, 0, buf_size);
+
+                  if (sprites[nsprites].buffer != NULL)
+                  {
+                     sprites[nsprites].file = NULL;
+                     ++argv, --argc;
+
+                     if (create_sprite(sprites+nsprites++, &argc, &argv))
+                     {
+                        result = 1; /* still ok */
+                        continue;
+                     }
+
+                     break; /* error */
+                  }
+               }
+
+               /* Overflow, or OOM */
+               fprintf(stderr, "simpleover: %s: sprite too large\n", argv[0]);
+               break;
+            }
+
+            else
+            {
+               fprintf(stderr, "simpleover: %s: invalid sprite (%u,%u)\n",
+                  argv[0], sprites[nsprites].width, sprites[nsprites].height);
+               break;
+            }
+         }
+
+         else
+         {
+            fprintf(stderr, "simpleover: %s: too many sprites\n", argv[0]);
+            break;
+         }
+      }
+
+      else if (strncmp(argv[0], "--add=", 6) == 0)
+      {
+         const char *name = argv[0]+6;
+         int isprite = nsprites;
+
+         ++argv, --argc;
+
+         while (--isprite >= 0)
+         {
+            if (strcmp(sprites[isprite].name, name) == 0)
+            {
+               if (!add_sprite(output, out_buf, sprites+isprite, &argc, &argv))
+                  goto out; /* error in add_sprite */
+
+               break; 
+            }
+         }
+
+         if (isprite < 0) /* sprite not found */
+         {
+            fprintf(stderr, "simpleover: --add='%s': sprite not found\n", name);
+            break;
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "simpleover: %s: unrecognized operation\n", argv[0]);
+         break;
+      }
+
+      result = 1; /* ok  */
+   }
+
+   /* Clean up the cache of sprites: */
+out:
+   while (--nsprites >= 0)
+   {
+      if (sprites[nsprites].buffer != NULL)
+         free(sprites[nsprites].buffer);
+
+      if (sprites[nsprites].file != NULL)
+         (void)fclose(sprites[nsprites].file);
+   }
+
+   return result;
+}
+
+int main(int argc, const char **argv)
+{
+   int result = 1; /* default to fail */
+
+   if (argc >= 2)
+   {
+      int argi = 2;
+      const char *output = NULL;
+      png_image image;
+
+      if (argc > 2 && argv[2][0] != '-'/*an operation*/)
+      {
+         output = argv[2];
+         argi = 3;
+      }
+
+      image.version = PNG_IMAGE_VERSION;
+      image.opaque = NULL;
+
+      if (png_image_begin_read_from_file(&image, argv[1]))
+      {
+         png_bytep buffer;
+
+         image.format = PNG_FORMAT_RGB; /* 24-bit RGB */
+
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         if (buffer != NULL)
+         {
+            png_color background = {0, 0xff, 0}; /* fully saturated green */
+
+            if (png_image_finish_read(&image, &background, buffer,
+               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
+            {
+               /* At this point png_image_finish_read has cleaned up the
+                * allocated data in png_image, and only the buffer needs to be
+                * freed.
+                *
+                * Perform the remaining operations:
+                */
+               if (simpleover_process(&image, buffer, argc-argi, argv+argi))
+               {
+                  /* Write the output: */
+                  if ((output != NULL &&
+                       png_image_write_to_file(&image, output,
+                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                        NULL/*colormap*/)) ||
+                      (output == NULL &&
+                       png_image_write_to_stdio(&image, stdout,
+                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                        NULL/*colormap*/)))
+                     result = 0;
+
+                  else
+                     fprintf(stderr, "simpleover: write %s: %s\n",
+                        output == NULL ? "stdout" : output, image.message);
+               }
+
+               /* else simpleover_process writes an error message */
+            }
+
+            else
+               fprintf(stderr, "simpleover: read %s: %s\n", argv[1],
+                   image.message);
+
+            free(buffer);
+         }
+
+         else
+         {
+            fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+
+            /* This is the only place where a 'free' is required; libpng does
+             * the cleanup on error and success, but in this case we couldn't
+             * complete the read because of running out of memory.
+             */
+            png_image_free(&image);
+         }
+      }
+
+      else
+      {
+         /* Failed to read the first argument: */
+         fprintf(stderr, "simpleover: %s: %s\n", argv[1], image.message);
+      }
+   }
+
+   else
+   {
+      /* Usage message */
+      fprintf(stderr,
+         "simpleover: usage: simpleover background.png [output.png]\n"
+         "  Output 'background.png' as a 24-bit RGB PNG file in 'output.png'\n"
+         "   or, if not given, stdout.  'background.png' will be composited\n"
+         "   on fully saturated green.\n"
+         "\n"
+         "  Optionally, before output, process additional PNG files:\n"
+         "\n"
+         "   --sprite=width,height,name {[--at=x,y] {sprite.png}}\n"
+         "    Produce a transparent sprite of size (width,height) and with\n"
+         "     name 'name'.\n"
+         "    For each sprite.png composite it using a Porter-Duff 'Over'\n"
+         "     operation at offset (x,y) in the sprite (defaulting to (0,0)).\n"
+         "     Input PNGs will be truncated to the area of the sprite.\n"
+         "\n"
+         "   --add='name' {x,y}\n"
+         "    Optionally, before output, composite a sprite, 'name', which\n"
+         "     must have been previously produced using --sprite, at each\n"
+         "     offset (x,y) in the output image.  Each sprite must fit\n"
+         "     completely within the output image.\n"
+         "\n"
+         "  PNG files are processed in the order they occur on the command\n"
+         "  line and thus the first PNG processed appears as the bottommost\n"
+         "  in the output image.\n");
+   }
+
+   return result;
+}
+#endif /* SIMPLIFIED_READ */
--- a/contrib/gregbook/Makefile.mingw32
+++ b/contrib/gregbook/Makefile.mingw32
@@ -47,7 +47,8 @@ CC = gcc
 #CC = i386-mingw32msvc-gcc #	e.g., Linux -> Win32 cross-compilation
 LD = $(CC)
 RM = rm -f
-CFLAGS = -O -Wall $(INCS) $(MINGW_CCFLAGS)
+CPPFLAGS = $(INCS)
+CFLAGS = -O -Wall $(MINGW_CCFLAGS)
 # [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
 # [-ansi, -pedantic and -W can also be used]
 LDFLAGS = $(MINGW_LDFLAGS)
@@ -85,10 +86,10 @@ EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
 # implicit make rules -------------------------------------------------------

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

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


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

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

-PNGINC = -I/usr/local/include/libpng15
-PNGLIB = -L/usr/local/lib -lpng15	  # dynamically linked against libpng
-#PNGLIB = /usr/local/lib/libpng15.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
@@ -53,7 +53,8 @@ CC = cc
 LD = cc
 RM = rm -f
 # ABI must be the same as that used to build libpng.
-ABI=
+ABI =
+CPPFLAGS =
 CFLAGS = $(ABI) -O -fullwarn $(INCS)
 LDFLAGS = $(ABI)
 O = .o
@@ -73,7 +74,7 @@ EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
 # implicit make rules -------------------------------------------------------

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


 # dependencies --------------------------------------------------------------
--- a/contrib/gregbook/Makefile.unx
+++ b/contrib/gregbook/Makefile.unx
@@ -26,14 +26,14 @@
 # macros --------------------------------------------------------------------

 #PNGDIR = /usr/local/lib
-#PNGINC = -I/usr/local/include/libpng15
-#PNGLIBd = -L$(PNGDIR) -lpng15 # dynamically linked, installed libpng
-#PNGLIBs = $(PNGDIR)/libpng15.a # statically linked, installed libpng
+#PNGINC = -I/usr/local/include/libpng16
+#PNGLIBd = -L$(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) -lpng15	# dynamically linked
+PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng16	# dynamically linked
 PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng

 ZDIR = /usr/local/lib
@@ -59,14 +59,16 @@ INCS = $(PNGINC) $(ZINC) $(XINC)
 RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
 RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
 WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
-WLIBSs = $(PNGLIBs) $(ZLIBs)
+WLIBSs = $(PNGLIBs) $(ZLIBs) -lm

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

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


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

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


 # dependencies --------------------------------------------------------------
--- a/contrib/gregbook/readpng.c
+++ b/contrib/gregbook/readpng.c
@@ -55,8 +55,9 @@

 #include <stdio.h>
 #include <stdlib.h>
+#include <zlib.h>

-#include "png.h"        /* libpng header; includes zlib.h */
+#include "png.h"        /* libpng header */
 #include "readpng.h"    /* typedefs, common macros, public prototypes */

 /* future versions of libpng will provide this macro: */
@@ -99,7 +100,8 @@ int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)

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

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

@@ -214,6 +216,10 @@ uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
     * libpng function */

    if (setjmp(png_jmpbuf(png_ptr))) {
+        free(image_data);
+        image_data = NULL;
+        free(row_pointers);
+        row_pointers = NULL;
        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
        return NULL;
    }
--- a/contrib/gregbook/readpng2.c
+++ b/contrib/gregbook/readpng2.c
@@ -69,6 +69,7 @@ static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
                                 png_uint_32 row_num, int pass);
 static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr);
 static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg);
+static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg);



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

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

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

@@ -136,29 +137,23 @@ int readpng2_init(mainprog_info *mainprog_ptr)
     * used, i.e., all chunks recognized by libpng except for IHDR, PLTE, IDAT,
     * IEND, tRNS, bKGD, gAMA, and sRGB (small performance improvement) */
    {
-        /* These byte strings were copied from png.h.  If a future libpng
-         * version recognizes more chunks, add them to this list.  If a
-         * future version of readpng2.c recognizes more chunks, delete them
-         * from this list. */
-        static /* const */ png_byte chunks_to_ignore[] = {
-             99,  72,  82,  77, '\0',  /* cHRM */
-            104,  73,  83,  84, '\0',  /* hIST */
-            105,  67,  67,  80, '\0',  /* iCCP */
-            105,  84,  88, 116, '\0',  /* iTXt */
-            111,  70,  70, 115, '\0',  /* oFFs */
-            112,  67,  65,  76, '\0',  /* pCAL */
-            112,  72,  89, 115, '\0',  /* pHYs */
-            115,  66,  73,  84, '\0',  /* sBIT */
-            115,  67,  65,  76, '\0',  /* sCAL */
-            115,  80,  76,  84, '\0',  /* sPLT */
-            115,  84,  69,  82, '\0',  /* sTER */
-            116,  69,  88, 116, '\0',  /* tEXt */
-            116,  73,  77,  69, '\0',  /* tIME */
-            122,  84,  88, 116, '\0'   /* zTXt */
-        };
+        /* These byte strings were copied from png.h.  If a future version
+         * of readpng2.c recognizes more chunks, add them to this list.
+         */
+        static PNG_CONST png_byte chunks_to_process[] = {
+            98,  75,  71,  68, '\0',  /* bKGD */
+           103,  65,  77,  65, '\0',  /* gAMA */
+           115,  82,  71,  66, '\0',  /* sRGB */
+           };

-        png_set_keep_unknown_chunks(png_ptr, 1 /* PNG_HANDLE_CHUNK_NEVER */,
-          chunks_to_ignore, sizeof(chunks_to_ignore)/5);
+       /* Ignore all chunks except for IHDR, PLTE, tRNS, IDAT, and IEND */
+       png_set_keep_unknown_chunks(png_ptr, -1 /* PNG_HANDLE_CHUNK_NEVER */,
+          NULL, -1);
+
+       /* But do not ignore chunks in the "chunks_to_process" list */
+       png_set_keep_unknown_chunks(png_ptr,
+          0 /* PNG_HANDLE_CHUNK_AS_DEFAULT */, chunks_to_process,
+          sizeof(chunks_to_process)/5);
    }
 #endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */

@@ -453,6 +448,8 @@ static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)

    /* all done */

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

@@ -473,7 +470,12 @@ void readpng2_cleanup(mainprog_info *mainprog_ptr)
 }


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


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

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

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

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

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

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

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

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

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

    rpng_x_cleanup();

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

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

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

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

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

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

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

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

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

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

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

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

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


--- a/contrib/gregbook/writepng.c
+++ b/contrib/gregbook/writepng.c
@@ -55,8 +55,9 @@


 #include <stdlib.h>     /* for exit() prototype */
+#include <zlib.h>

-#include "png.h"        /* libpng header; includes zlib.h and setjmp.h */
+#include "png.h"        /* libpng header, includes setjmp.h */
 #include "writepng.h"   /* typedefs, common macros, public prototypes */


@@ -89,7 +90,7 @@ int writepng_init(mainprog_info *mainprog_ptr)

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

-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+    png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), mainprog_ptr,
      writepng_error_handler, NULL);
    if (!png_ptr)
        return 4;   /* out of memory */
--- a/contrib/libtests/fakepng.c
+++ b/contrib/libtests/fakepng.c
@@ -0,0 +1,57 @@
+/* Fake a PNG - just write it out directly. */
+#include <stdio.h>
+#include <zlib.h> /* for crc32 */
+
+void
+put_uLong(uLong val)
+{
+   putchar(val >> 24);
+   putchar(val >> 16);
+   putchar(val >>  8);
+   putchar(val >>  0);
+}
+
+void
+put_chunk(const unsigned char *chunk, uInt length)
+{
+   uLong crc;
+
+   put_uLong(length-4); /* Exclude the tag */
+
+   fwrite(chunk, length, 1, stdout);
+
+   crc = crc32(0, Z_NULL, 0);
+   put_uLong(crc32(crc, chunk, length));
+}
+
+const unsigned char signature[] =
+{
+   137, 80, 78, 71, 13, 10, 26, 10
+};
+
+const unsigned char IHDR[] =
+{
+   73, 72, 68, 82, /* IHDR */
+   0, 0, 0, 1, /* width */
+   0, 0, 0, 1, /* height */
+   1, /* bit depth */
+   0, /* color type: greyscale */
+   0, /* compression method */
+   0, /* filter method */
+   0  /* interlace method: none */
+};
+
+const unsigned char unknown[] =
+{
+   'u', 'n', 'K', 'n' /* "unKn" - private safe to copy */
+};
+
+int
+main(void)
+{
+   fwrite(signature, sizeof signature, 1, stdout);
+   put_chunk(IHDR, sizeof IHDR);
+
+   for (;;)
+      put_chunk(unknown, sizeof unknown);
+}
--- a/contrib/libtests/gentests.sh
+++ b/contrib/libtests/gentests.sh
@@ -0,0 +1,102 @@
+#!/bin/sh
+#
+# Copyright (c) 2013 John Cunningham Bowler
+#
+# Last changed in libpng 1.6.0 [February 14, 2013]
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Generate a set of PNG test images.  The images are generated in a
+# sub-directory called 'tests' by default, however a command line argument will
+# change that name.  The generation requires a built version of makepng in the
+# current directory.
+#
+usage(){
+   exec >&2
+   echo "$0 [<directory>]"
+   echo '  Generate a set of PNG test files in "directory" ("tests" by default)'
+   exit 1
+}
+
+mp="$PWD/makepng"
+test -x "$mp" || {
+   exec >&2
+   echo "$0: the 'makepng' program must exist"
+   echo "  in the directory within which this program:"
+   echo "    $mp"
+   echo "  is executed"
+   usage
+}
+
+# Just one argument: the directory
+testdir="tests"
+test $# -gt 1 && {
+   testdir="$1"
+   shift
+}
+test $# -eq 0 || usage
+
+# Take care not to clobber something
+if test -e "$testdir"
+then
+   test -d "$testdir" || usage
+else
+   # mkdir -p isn't portable, so do the following
+   mkdir "$testdir" 2>/dev/null || mkdir -p "$testdir" || usage
+fi
+
+# This fails in a very satisfactory way if it's not accessible
+cd "$testdir"
+:>"test$$.png" || {
+   exec >&2
+   echo "$testdir: directory not writable"
+   usage
+}
+rm "test$$.png" || {
+   exec >&2
+   echo "$testdir: you have create but not write privileges here."
+   echo "  This is unexpected.  You have a spurion; "'"'"test$$.png"'"'"."
+   echo "  You need to remove this yourself.  Try a different directory."
+   exit 1
+}
+
+# Now call makepng ($mp) to create every file we can think of with a
+# reasonable name
+doit(){
+   for gamma in "" --sRGB --linear --1.8
+   do
+      case "$gamma" in
+         "")
+            gname=;;
+         --sRGB)
+            gname="-srgb";;
+         --linear)
+            gname="-lin";;
+         --1.8)
+            gname="-18";;
+         *)
+            gname="-$gamma";;
+      esac
+      "$mp" $gamma "$1" "$2" "test-$1-$2$gname.png"
+   done
+}
+#
+for ct in gray palette
+do
+   for bd in 1 2 4 8
+   do
+      doit "$ct" "$bd"
+   done
+done
+#
+doit "gray" "16"
+#
+for ct in gray-alpha rgb rgb-alpha
+do
+   for bd in 8 16
+   do
+      doit "$ct" "$bd"
+   done
+done
--- a/contrib/libtests/makepng.c
+++ b/contrib/libtests/makepng.c
--- a/contrib/libtests/pngimage.c
+++ b/contrib/libtests/pngimage.c
--- a/contrib/libtests/pngstest.c
+++ b/contrib/libtests/pngstest.c
--- a/contrib/libtests/pngunknown.c
+++ b/contrib/libtests/pngunknown.c
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
--- a/contrib/libtests/readpng.c
+++ b/contrib/libtests/readpng.c
@@ -0,0 +1,104 @@
+/* readpng.c
+ *
+ * Copyright (c) 2013 John Cunningham Bowler
+ *
+ * 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
+ * and license in png.h
+ *
+ * Load an arbitrary number of PNG files (from the command line, or, if there
+ * are no arguments on the command line, from stdin) then run a time test by
+ * reading each file by row.  The test does nothing with the read result and
+ * does no transforms.  The only output is a time as a floating point number of
+ * seconds with 9 decimal digits.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+static int
+read_png(FILE *fp)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
+   png_infop info_ptr = NULL;
+   png_bytep row = NULL, display = NULL;
+
+   if (png_ptr == NULL)
+      return 0;
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      if (row != NULL) free(row);
+      if (display != NULL) free(display);
+      return 0;
+   }
+
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, NULL, 0);
+
+   png_read_info(png_ptr, info_ptr);
+
+   {
+      png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+      row = malloc(rowbytes);
+      display = malloc(rowbytes);
+
+      if (row == NULL || display == NULL)
+         png_error(png_ptr, "OOM allocating row buffers");
+
+      {
+         png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
+         int passes = png_set_interlace_handling(png_ptr);
+         int pass;
+
+         png_start_read_image(png_ptr);
+
+         for (pass = 0; pass < passes; ++pass)
+         {
+            png_uint_32 y = height;
+
+            /* NOTE: this trashes the row each time; interlace handling won't
+             * work, but this avoids memory thrashing for speed testing.
+             */
+            while (y-- > 0)
+               png_read_row(png_ptr, row, display);
+         }
+      }
+   }
+
+   /* Make sure to read to the end of the file: */
+   png_read_end(png_ptr, info_ptr);
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   free(row);
+   free(display);
+   return 1;
+}
+
+int
+main(void)
+{
+   /* Exit code 0 on success. */
+   return !read_png(stdin);
+}
--- a/contrib/libtests/tarith.c
+++ b/contrib/libtests/tarith.c
@@ -0,0 +1,999 @@
+
+/* tarith.c
+ *
+ * Copyright (c) 2011-2013 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Test internal arithmetic functions of libpng.
+ *
+ * This code must be linked against a math library (-lm), but does not require
+ * libpng or zlib to work.  Because it includes the complete source of 'png.c'
+ * it tests the code with whatever compiler options are used to build it.
+ * Changing these options can substantially change the errors in the
+ * calculations that the compiler chooses!
+ */
+#define _POSIX_SOURCE 1
+#define _ISOC99_SOURCE 1
+
+/* Obtain a copy of the code to be tested (plus other things), disabling
+ * stuff that is not required.
+ */
+#include <math.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <assert.h>
+
+#include "../../pngpriv.h"
+
+#define png_error png_warning
+
+void png_warning(png_const_structrp png_ptr, png_const_charp msg)
+{
+   fprintf(stderr, "validation: %s\n", msg);
+}
+
+#define png_fixed_error png_fixed_warning
+
+void png_fixed_warning(png_const_structrp png_ptr, png_const_charp msg)
+{
+   fprintf(stderr, "overflow in: %s\n", msg);
+}
+
+#define png_set_error_fn(pp, ep, efp, wfp) ((void)0)
+#define png_malloc(pp, s) malloc(s)
+#define png_malloc_warn(pp, s) malloc(s)
+#define png_malloc_base(pp, s) malloc(s)
+#define png_calloc(pp, s) calloc(1, (s))
+#define png_free(pp, s) free(s)
+
+#define png_safecat(b, sb, pos, str) (pos)
+#define png_format_number(start, end, format, number) (start)
+
+#define crc32(crc, pp, s) (crc)
+#define inflateReset(zs) Z_OK
+
+#define png_create_struct(type) (0)
+#define png_destroy_struct(pp) ((void)0)
+#define png_create_struct_2(type, m, mm) (0)
+#define png_destroy_struct_2(pp, f, mm) ((void)0)
+
+#undef PNG_SIMPLIFIED_READ_SUPPORTED
+#undef PNG_SIMPLIFIED_WRITE_SUPPORTED
+#undef PNG_USER_MEM_SUPPORTED
+
+#include "../../png.c"
+
+/* Validate ASCII to fp routines. */
+static int verbose = 0;
+
+int validation_ascii_to_fp(int count, int argc, char **argv)
+{
+   int    showall = 0;
+   double max_error=2;      /* As a percentage error-in-last-digit/.5 */
+   double max_error_abs=17; /* Used when precision is DBL_DIG */
+   double max = 0;
+   double max_abs = 0;
+   double test = 0; /* Important to test this. */
+   int    precision = 5;
+   int    nonfinite = 0;
+   int    finite = 0;
+   int    ok = 0;
+   int    failcount = 0;
+   int    minorarith = 0;
+
+   while (--argc > 0)
+      if (strcmp(*++argv, "-a") == 0)
+         showall = 1;
+      else if (strcmp(*argv, "-e") == 0 && argc > 0)
+      {
+         --argc;
+         max_error = atof(*++argv);
+      }
+      else if (strcmp(*argv, "-E") == 0 && argc > 0)
+      {
+         --argc;
+         max_error_abs = atof(*++argv);
+      }
+      else
+      {
+         fprintf(stderr, "unknown argument %s\n", *argv);
+         return 1;
+      }
+
+   do
+   {
+      png_size_t index;
+      int state, failed = 0;
+      char buffer[64];
+
+      if (isfinite(test))
+         ++finite;
+      else
+         ++nonfinite;
+
+      if (verbose)
+         fprintf(stderr, "%.*g %d\n", DBL_DIG, test, precision);
+
+      /* Check for overflow in the buffer by setting a marker. */
+      memset(buffer, 71, sizeof buffer);
+
+      png_ascii_from_fp(0, buffer, precision+10, test, precision);
+
+      /* Allow for a three digit exponent, this stuff will fail if
+       * the exponent is bigger than this!
+       */
+      if (buffer[precision+7] != 71)
+      {
+         fprintf(stderr, "%g[%d] -> '%s'[%lu] buffer overflow\n", test,
+            precision, buffer, (unsigned long)strlen(buffer));
+         failed = 1;
+      }
+
+      /* Following are used for the number parser below and must be
+       * initialized to zero.
+       */
+      state = 0;
+      index = 0;
+      if (!isfinite(test))
+      {
+         /* Expect 'inf' */
+         if (test >= 0 && strcmp(buffer, "inf") ||
+             test <  0 && strcmp(buffer, "-inf"))
+         {
+            fprintf(stderr, "%g[%d] -> '%s' but expected 'inf'\n", test,
+               precision, buffer);
+            failed = 1;
+         }
+      }
+      else if (!png_check_fp_number(buffer, precision+10, &state, &index) ||
+          buffer[index] != 0)
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but has bad format ('%c')\n", test,
+         precision, buffer, buffer[index]);
+         failed = 1;
+      }
+      else if (PNG_FP_IS_NEGATIVE(state) && !(test < 0))
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but negative value not so reported\n",
+            test, precision, buffer);
+         failed = 1;
+         assert(!PNG_FP_IS_ZERO(state));
+         assert(!PNG_FP_IS_POSITIVE(state));
+      }
+      else if (PNG_FP_IS_ZERO(state) && !(test == 0))
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but zero value not so reported\n",
+            test, precision, buffer);
+         failed = 1;
+         assert(!PNG_FP_IS_NEGATIVE(state));
+         assert(!PNG_FP_IS_POSITIVE(state));
+      }
+      else if (PNG_FP_IS_POSITIVE(state) && !(test > 0))
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but postive value not so reported\n",
+            test, precision, buffer);
+         failed = 1;
+         assert(!PNG_FP_IS_NEGATIVE(state));
+         assert(!PNG_FP_IS_ZERO(state));
+      }
+      else
+      {
+         /* Check the result against the original. */
+         double out = atof(buffer);
+         double change = fabs((out - test)/test);
+         double allow = .5/pow(10,
+            (precision >= DBL_DIG) ? DBL_DIG-1 : precision-1);
+
+         /* NOTE: if you hit this error case are you compiling with gcc
+          * and -O0?  Try -O2 - the errors can accumulate if the FP
+          * code above is not optimized and may drift outside the .5 in
+          * DBL_DIG allowed.  In any case a small number of errors may
+          * occur (very small ones - 1 or 2%) because of rounding in the
+          * calculations, either in the conversion API or in atof.
+          */
+         if (change >= allow && (isfinite(out) ||
+             fabs(test/DBL_MAX) <= 1-allow))
+         {
+            double percent = (precision >= DBL_DIG) ? max_error_abs : max_error;
+            double allowp = (change-allow)*100/allow;
+
+            if (precision >= DBL_DIG)
+            {
+               if (max_abs < allowp) max_abs = allowp;
+            }
+
+            else
+            {
+               if (max < allowp) max = allowp;
+            }
+
+            if (showall || allowp >= percent)
+            {
+               fprintf(stderr,
+                  "%.*g[%d] -> '%s' -> %.*g number changed (%g > %g (%d%%))\n",
+                  DBL_DIG, test, precision, buffer, DBL_DIG, out, change, allow,
+                  (int)round(allowp));
+               failed = 1;
+            }
+            else
+               ++minorarith;
+         }
+      }
+
+      if (failed)
+         ++failcount;
+      else
+         ++ok;
+
+skip:
+      /* Generate a new number and precision. */
+      precision = rand();
+      if (precision & 1) test = -test;
+      precision >>= 1;
+
+      /* Generate random numbers. */
+      if (test == 0 || !isfinite(test))
+         test = precision+1;
+      else
+      {
+         /* Derive the exponent from the previous rand() value. */
+         int exponent = precision % (DBL_MAX_EXP - DBL_MIN_EXP) + DBL_MIN_EXP;
+         int tmp;
+         test = frexp(test * rand(), &tmp);
+         test = ldexp(test, exponent);
+         precision >>= 8; /* arbitrary */
+      }
+
+      /* This limits the precision to 32 digits, enough for standard
+       * IEEE implementations which have at most 15 digits.
+       */
+      precision = (precision & 0x1f) + 1;
+   }
+   while (--count);
+
+   printf("Tested %d finite values, %d non-finite, %d OK (%d failed) %d minor "
+      "arithmetic errors\n", finite, nonfinite, ok, failcount, minorarith);
+   printf(" Error with >=%d digit precision %.2f%%\n", DBL_DIG, max_abs);
+   printf(" Error with < %d digit precision %.2f%%\n", DBL_DIG, max);
+
+   return 0;
+}
+
+/* Observe that valid FP numbers have the forms listed in the PNG extensions
+ * specification:
+ *
+ * [+,-]{integer,integer.fraction,.fraction}[{e,E}[+,-]integer]
+ *
+ * Test each of these in turn, including invalid cases.
+ */
+typedef enum checkfp_state
+{
+   start, fraction, exponent, states
+} checkfp_state;
+
+/* The characters (other than digits) that characterize the states: */
+static const char none[] = "";
+static const char hexdigits[16] = "0123456789ABCDEF";
+
+static const struct
+{
+   const char *start; /* Characters valid at the start */
+   const char *end;   /* Valid characters that end the state */
+   const char *tests; /* Characters to test after 2 digits seen */
+}
+state_characters[states] =
+{
+   /* start:    */ { "+-.", ".eE", "+-.e*0369" },
+   /* fraction: */ { none, "eE",  "+-.E#0147" },
+   /* exponent: */ { "+-", none,  "+-.eE^0258" }
+};
+
+typedef struct
+{
+   char number[1024];  /* Buffer for number being tested */
+   int  limit;         /* Command line limit */
+   int  verbose;       /* Shadows global variable */
+   int  ctimes;        /* Number of numbers tested */
+   int  cmillions;     /* Count of millions of numbers */
+   int  cinvalid;      /* Invalid strings checked */
+   int  cnoaccept;     /* Characters not accepted */
+}
+checkfp_command;
+
+typedef struct
+{
+   int           cnumber;          /* Index into number string */
+   checkfp_state check_state;      /* Current number state */
+   int           at_start;         /* At start (first character) of state */
+   int           cdigits_in_state; /* Digits seen in that state */
+   int           limit;            /* Limit on same for checking all chars */
+   int           state;            /* Current parser state */
+   int           is_negative;      /* Number is negative */
+   int           is_zero;          /* Number is (still) zero */
+   int           number_was_valid; /* Previous character validity */
+}
+checkfp_control;
+
+static int check_all_characters(checkfp_command *co, checkfp_control c);
+
+static int check_some_characters(checkfp_command *co, checkfp_control c,
+   const char *tests);
+
+static int check_one_character(checkfp_command *co, checkfp_control c, int ch)
+{
+   /* Test this character (ch) to ensure the parser does the correct thing.
+    */
+   png_size_t index = 0;
+   const char test = (char)ch;
+   const int number_is_valid = png_check_fp_number(&test, 1, &c.state, &index);
+   const int character_accepted = (index == 1);
+
+   if (c.check_state != exponent && isdigit(ch) && ch != '0')
+      c.is_zero = 0;
+
+   if (c.check_state == start && c.at_start && ch == '-')
+      c.is_negative = 1;
+
+   if (isprint(ch))
+      co->number[c.cnumber++] = (char)ch;
+   else
+   {
+      co->number[c.cnumber++] = '<';
+      co->number[c.cnumber++] = hexdigits[(ch >> 4) & 0xf];
+      co->number[c.cnumber++] = hexdigits[ch & 0xf];
+      co->number[c.cnumber++] = '>';
+   }
+   co->number[c.cnumber] = 0;
+
+   if (co->verbose > 1)
+      fprintf(stderr, "%s\n", co->number);
+
+   if (++(co->ctimes) == 1000000)
+   {
+      if (co->verbose == 1)
+         fputc('.', stderr);
+      co->ctimes = 0;
+      ++(co->cmillions);
+   }
+
+   if (!number_is_valid)
+      ++(co->cinvalid);
+
+   if (!character_accepted)
+      ++(co->cnoaccept);
+
+   /* This should never fail (it's a serious bug if it does): */
+   if (index != 0 && index != 1)
+   {
+      fprintf(stderr, "%s: read beyond end of string (%lu)\n", co->number,
+         (unsigned long)index);
+      return 0;
+   }
+
+   /* Validate the new state, note that the PNG_FP_IS_ macros all return
+    * false unless the number is valid.
+    */
+   if (PNG_FP_IS_NEGATIVE(c.state) !=
+      (number_is_valid && !c.is_zero && c.is_negative))
+   {
+      fprintf(stderr, "%s: negative when it is not\n", co->number);
+      return 0;
+   }
+
+   if (PNG_FP_IS_ZERO(c.state) != (number_is_valid && c.is_zero))
+   {
+      fprintf(stderr, "%s: zero when it is not\n", co->number);
+      return 0;
+   }
+
+   if (PNG_FP_IS_POSITIVE(c.state) !=
+      (number_is_valid && !c.is_zero && !c.is_negative))
+   {
+      fprintf(stderr, "%s: positive when it is not\n", co->number);
+      return 0;
+   }
+
+   /* Testing a digit */
+   if (isdigit(ch))
+   {
+      if (!character_accepted)
+      {
+         fprintf(stderr, "%s: digit '%c' not accepted\n", co->number, ch);
+         return 0;
+      }
+
+      if (!number_is_valid)
+      {
+         fprintf(stderr, "%s: saw a digit (%c) but number not valid\n",
+            co->number, ch);
+         return 0;
+      }
+
+      ++c.cdigits_in_state;
+      c.at_start = 0;
+      c.number_was_valid = 1;
+
+      /* Continue testing characters in this state.  Either test all of
+       * them or, if we have already seen one digit in this state, just test a
+       * limited set.
+       */
+      if (c.cdigits_in_state < 1)
+         return check_all_characters(co, c);
+
+      else
+         return check_some_characters(co, c,
+            state_characters[c.check_state].tests);
+   }
+
+   /* A non-digit; is it allowed here? */
+   else if (((ch == '+' || ch == '-') && c.check_state != fraction &&
+               c.at_start) ||
+            (ch == '.' && c.check_state == start) ||
+            ((ch == 'e' || ch == 'E') && c.number_was_valid &&
+               c.check_state != exponent))
+   {
+      if (!character_accepted)
+      {
+         fprintf(stderr, "%s: character '%c' not accepted\n", co->number, ch);
+         return 0;
+      }
+
+      /* The number remains valid after start of fraction but nowhere else. */
+      if (number_is_valid && (c.check_state != start || ch != '.'))
+      {
+         fprintf(stderr, "%s: saw a non-digit (%c) but number valid\n",
+            co->number, ch);
+         return 0;
+      }
+
+      c.number_was_valid = number_is_valid;
+
+      /* Check for a state change.  When changing to 'fraction' if the number
+       * is valid at this point set the at_start to false to allow an exponent
+       * 'e' to come next.
+       */
+      if (c.check_state == start && ch == '.')
+      {
+         c.check_state = fraction;
+         c.at_start = !number_is_valid;
+         c.cdigits_in_state = 0;
+         c.limit = co->limit;
+         return check_all_characters(co, c);
+      }
+
+      else if (c.check_state < exponent && (ch == 'e' || ch == 'E'))
+      {
+         c.check_state = exponent;
+         c.at_start = 1;
+         c.cdigits_in_state = 0;
+         c.limit = co->limit;
+         return check_all_characters(co, c);
+      }
+
+      /* Else it was a sign, and the state doesn't change. */
+      else
+      {
+         if (ch != '-' && ch != '+')
+         {
+            fprintf(stderr, "checkfp: internal error (1)\n");
+            return 0;
+         }
+
+         c.at_start = 0;
+         return check_all_characters(co, c);
+      }
+   }
+
+   /* Testing an invalid character */
+   else
+   {
+      if (character_accepted)
+      {
+         fprintf(stderr, "%s: character '%c' [0x%.2x] accepted\n", co->number,
+            ch, ch);
+         return 0;
+      }
+
+      if (number_is_valid != c.number_was_valid)
+      {
+         fprintf(stderr,
+            "%s: character '%c' [0x%.2x] changed number validity\n", co->number,
+            ch, ch);
+         return 0;
+      }
+
+      /* Do nothing - the parser has stuck; return success and keep going with
+       * the next character.
+       */
+   }
+
+   /* Successful return (the caller will try the next character.) */
+   return 1;
+}
+
+static int check_all_characters(checkfp_command *co, checkfp_control c)
+{
+   int ch;
+
+   if (c.cnumber+4 < sizeof co->number) for (ch=0; ch<256; ++ch)
+   {
+      if (!check_one_character(co, c, ch))
+         return 0;
+   }
+
+   return 1;
+}
+
+static int check_some_characters(checkfp_command *co, checkfp_control c,
+   const char *tests)
+{
+   int i;
+
+   --(c.limit);
+
+   if (c.cnumber+4 < sizeof co->number && c.limit >= 0)
+   {
+      if (c.limit > 0) for (i=0; tests[i]; ++i)
+      {
+         if (!check_one_character(co, c, tests[i]))
+               return 0;
+      }
+
+      /* At the end check all the characters. */
+      else
+         return check_all_characters(co, c);
+   }
+
+   return 1;
+}
+
+int validation_checkfp(int count, int argc, char **argv)
+{
+   int result;
+   checkfp_command command;
+   checkfp_control control;
+
+   command.number[0] = 0;
+   command.limit = 3;
+   command.verbose = verbose;
+   command.ctimes = 0;
+   command.cmillions = 0;
+   command.cinvalid = 0;
+   command.cnoaccept = 0;
+
+   while (--argc > 0)
+   {
+      ++argv;
+      if (argc > 1 && strcmp(*argv, "-l") == 0)
+      {
+         --argc;
+         command.limit = atoi(*++argv);
+      }
+
+      else
+      {
+         fprintf(stderr, "unknown argument %s\n", *argv);
+         return 1;
+      }
+   }
+
+   control.cnumber = 0;
+   control.check_state = start;
+   control.at_start = 1;
+   control.cdigits_in_state = 0;
+   control.limit = command.limit;
+   control.state = 0;
+   control.is_negative = 0;
+   control.is_zero = 1;
+   control.number_was_valid = 0;
+
+   result = check_all_characters(&command, control);
+
+   printf("checkfp: %s: checked %d,%.3d,%.3d,%.3d strings (%d invalid)\n",
+      result ? "pass" : "FAIL", command.cmillions / 1000,
+      command.cmillions % 1000, command.ctimes / 1000, command.ctimes % 1000,
+      command.cinvalid);
+
+   return result;
+}
+
+int validation_muldiv(int count, int argc, char **argv)
+{
+   int tested = 0;
+   int overflow = 0;
+   int error = 0;
+   int error64 = 0;
+   int passed = 0;
+   int randbits = 0;
+   png_uint_32 randbuffer;
+   png_fixed_point a;
+   png_int_32 times, div;
+
+   while (--argc > 0)
+      {
+         fprintf(stderr, "unknown argument %s\n", *++argv);
+         return 1;
+      }
+
+   /* Find out about the random number generator. */
+   randbuffer = RAND_MAX;
+   while (randbuffer != 0) ++randbits, randbuffer >>= 1;
+   printf("Using random number generator that makes %d bits\n", randbits);
+   for (div=0; div<32; div += randbits)
+      randbuffer = (randbuffer << randbits) ^ rand();
+
+   a = 0;
+   times = div = 0;
+   do
+   {
+      png_fixed_point result;
+      /* NOTE: your mileage may vary, a type is required below that can
+       * hold 64 bits or more, if floating point is used a 64 bit or
+       * better mantissa is required.
+       */
+      long long int fp, fpround;
+      unsigned long hi, lo;
+      int ok;
+
+      /* Check the values, png_64bit_product can only handle positive
+       * numbers, so correct for that here.
+       */
+      {
+         long u1, u2;
+         int n = 0;
+         if (a < 0) u1 = -a, n = 1; else u1 = a;
+         if (times < 0) u2 = -times, n = !n; else u2 = times;
+         png_64bit_product(u1, u2, &hi, &lo);
+         if (n)
+         {
+            /* -x = ~x+1 */
+            lo = ((~lo) + 1) & 0xffffffff;
+            hi = ~hi;
+            if (lo == 0) ++hi;
+         }
+      }
+
+      fp = a;
+      fp *= times;
+      if ((fp & 0xffffffff) != lo || ((fp >> 32) & 0xffffffff) != hi)
+      {
+         fprintf(stderr, "png_64bit_product %d * %d -> %lx|%.8lx not %llx\n",
+            a, times, hi, lo, fp);
+         ++error64;
+      }
+
+      if (div != 0)
+      {
+         /* Round - this is C round to zero. */
+         if ((fp < 0) != (div < 0))
+           fp -= div/2;
+         else
+           fp += div/2;
+
+         fp /= div;
+         fpround = fp;
+         /* Assume 2's complement here: */
+         ok = fpround <= PNG_UINT_31_MAX &&
+              fpround >= -1-(long long int)PNG_UINT_31_MAX;
+         if (!ok) ++overflow;
+      }
+      else
+        ok = 0, ++overflow, fpround = fp/*misleading*/;
+
+      if (verbose)
+         fprintf(stderr, "TEST %d * %d / %d -> %lld (%s)\n", a, times, div,
+            fp, ok ? "ok" : "overflow");
+
+      ++tested;
+      if (png_muldiv(&result, a, times, div) != ok)
+      {
+         ++error;
+         if (ok)
+             fprintf(stderr, "%d * %d / %d -> overflow (expected %lld)\n", a,
+                times, div, fp);
+         else
+             fprintf(stderr, "%d * %d / %d -> %d (expected overflow %lld)\n", a,
+                times, div, result, fp);
+      }
+      else if (ok && result != fpround)
+      {
+         ++error;
+         fprintf(stderr, "%d * %d / %d -> %d not %lld\n", a, times, div, result,
+            fp);
+      }
+      else
+         ++passed;
+
+      /* Generate three new values, this uses rand() and rand() only returns
+       * up to RAND_MAX.
+       */
+      /* CRUDE */
+      a += times;
+      times += div;
+      div = randbuffer;
+      randbuffer = (randbuffer << randbits) ^ rand();
+   }
+   while (--count > 0);
+
+   printf("%d tests including %d overflows, %d passed, %d failed (%d 64 bit "
+      "errors)\n", tested, overflow, passed, error, error64);
+   return 0;
+}
+
+/* When FP is on this just becomes a speed test - compile without FP to get real
+ * validation.
+ */
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+#define LN2 .000010576586617430806112933839 /* log(2)/65536 */
+#define L2INV 94548.46219969910586572651    /* 65536/log(2) */
+
+/* For speed testing, need the internal functions too: */
+static png_uint_32 png_log8bit(unsigned x)
+{
+   if (x > 0)
+      return (png_uint_32)floor(.5-log(x/255.)*L2INV);
+
+   return 0xffffffff;
+}
+
+static png_uint_32 png_log16bit(png_uint_32 x)
+{
+   if (x > 0)
+      return (png_uint_32)floor(.5-log(x/65535.)*L2INV);
+
+   return 0xffffffff;
+}
+
+static png_uint_32 png_exp(png_uint_32 x)
+{
+   return (png_uint_32)floor(.5 + exp(x * -LN2) * 0xffffffffU);
+}
+
+static png_byte png_exp8bit(png_uint_32 log)
+{
+   return (png_byte)floor(.5 + exp(log * -LN2) * 255);
+}
+
+static png_uint_16 png_exp16bit(png_uint_32 log)
+{
+   return (png_uint_16)floor(.5 + exp(log * -LN2) * 65535);
+}
+#endif /* FLOATING_ARITHMETIC */
+
+int validation_gamma(int argc, char **argv)
+{
+   double gamma[9] = { 2.2, 1.8, 1.52, 1.45, 1., 1/1.45, 1/1.52, 1/1.8, 1/2.2 };
+   double maxerr;
+   int i, silent=0, onlygamma=0;
+
+   /* Silence the output with -s, just test the gamma functions with -g: */
+   while (--argc > 0)
+      if (strcmp(*++argv, "-s") == 0)
+         silent = 1;
+      else if (strcmp(*argv, "-g") == 0)
+         onlygamma = 1;
+      else
+      {
+         fprintf(stderr, "unknown argument %s\n", *argv);
+         return 1;
+      }
+
+   if (!onlygamma)
+   {
+      /* First validate the log functions: */
+      maxerr = 0;
+      for (i=0; i<256; ++i)
+      {
+         double correct = -log(i/255.)/log(2.)*65536;
+         double error = png_log8bit(i) - correct;
+
+         if (i != 0 && fabs(error) > maxerr)
+            maxerr = fabs(error);
+
+         if (i == 0 && png_log8bit(i) != 0xffffffff ||
+             i != 0 && png_log8bit(i) != floor(correct+.5))
+         {
+            fprintf(stderr, "8 bit log error: %d: got %u, expected %f\n",
+               i, png_log8bit(i), correct);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 8 bit log error = %f\n", maxerr);
+
+      maxerr = 0;
+      for (i=0; i<65536; ++i)
+      {
+         double correct = -log(i/65535.)/log(2.)*65536;
+         double error = png_log16bit(i) - correct;
+
+         if (i != 0 && fabs(error) > maxerr)
+            maxerr = fabs(error);
+
+         if (i == 0 && png_log16bit(i) != 0xffffffff ||
+             i != 0 && png_log16bit(i) != floor(correct+.5))
+         {
+            if (error > .68) /* By experiment error is less than .68 */
+            {
+               fprintf(stderr, "16 bit log error: %d: got %u, expected %f"
+                  " error: %f\n", i, png_log16bit(i), correct, error);
+            }
+         }
+      }
+
+      if (!silent)
+         printf("maximum 16 bit log error = %f\n", maxerr);
+
+      /* Now exponentiations. */
+      maxerr = 0;
+      for (i=0; i<=0xfffff; ++i)
+      {
+         double correct = exp(-i/65536. * log(2.)) * (65536. * 65536);
+         double error = png_exp(i) - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > 1883) /* By experiment. */
+         {
+            fprintf(stderr, "32 bit exp error: %d: got %u, expected %f"
+                  " error: %f\n", i, png_exp(i), correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 32 bit exp error = %f\n", maxerr);
+
+      maxerr = 0;
+      for (i=0; i<=0xfffff; ++i)
+      {
+         double correct = exp(-i/65536. * log(2.)) * 255;
+         double error = png_exp8bit(i) - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > .50002) /* By experiment */
+         {
+            fprintf(stderr, "8 bit exp error: %d: got %u, expected %f"
+                  " error: %f\n", i, png_exp8bit(i), correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 8 bit exp error = %f\n", maxerr);
+
+      maxerr = 0;
+      for (i=0; i<=0xfffff; ++i)
+      {
+         double correct = exp(-i/65536. * log(2.)) * 65535;
+         double error = png_exp16bit(i) - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > .524) /* By experiment */
+         {
+            fprintf(stderr, "16 bit exp error: %d: got %u, expected %f"
+                  " error: %f\n", i, png_exp16bit(i), correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 16 bit exp error = %f\n", maxerr);
+   } /* !onlygamma */
+
+   /* Test the overall gamma correction. */
+   for (i=0; i<9; ++i)
+   {
+      unsigned j;
+      double g = gamma[i];
+      png_fixed_point gfp = floor(g * PNG_FP_1 + .5);
+
+      if (!silent)
+         printf("Test gamma %f\n", g);
+
+      maxerr = 0;
+      for (j=0; j<256; ++j)
+      {
+         double correct = pow(j/255., g) * 255;
+         png_byte out = png_gamma_8bit_correct(j, gfp);
+         double error = out - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (out != floor(correct+.5))
+         {
+            fprintf(stderr, "8bit %d ^ %f: got %d expected %f error %f\n",
+               j, g, out, correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("gamma %f: maximum 8 bit error %f\n", g, maxerr);
+
+      maxerr = 0;
+      for (j=0; j<65536; ++j)
+      {
+         double correct = pow(j/65535., g) * 65535;
+         png_uint_16 out = png_gamma_16bit_correct(j, gfp);
+         double error = out - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > 1.62)
+         {
+            fprintf(stderr, "16bit %d ^ %f: got %d expected %f error %f\n",
+               j, g, out, correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("gamma %f: maximum 16 bit error %f\n", g, maxerr);
+   }
+
+   return 0;
+}
+
+/**************************** VALIDATION TESTS ********************************/
+/* Various validation routines are included herein, they require some
+ * definition for png_warning and png_error, seetings of VALIDATION:
+ *
+ * 1: validates the ASCII to floating point conversions
+ * 2: validates png_muldiv
+ * 3: accuracy test of fixed point gamma tables
+ */
+
+/* The following COUNT (10^8) takes about 1 hour on a 1GHz Pentium IV
+ * processor.
+ */
+#define COUNT 1000000000
+
+int main(int argc, char **argv)
+{
+   int count = COUNT;
+
+   while (argc > 1)
+   {
+      if (argc > 2 && strcmp(argv[1], "-c") == 0)
+      {
+         count = atoi(argv[2]);
+         argc -= 2;
+         argv += 2;
+      }
+
+      else if (strcmp(argv[1], "-v") == 0)
+      {
+         ++verbose;
+         --argc;
+         ++argv;
+      }
+
+      else
+         break;
+   }
+
+   if (count > 0 && argc > 1)
+   {
+      if (strcmp(argv[1], "ascii") == 0)
+         return validation_ascii_to_fp(count, argc-1, argv+1);
+      else if (strcmp(argv[1], "checkfp") == 0)
+         return validation_checkfp(count, argc-1, argv+1);
+      else if (strcmp(argv[1], "muldiv") == 0)
+         return validation_muldiv(count, argc-1, argv+1);
+      else if (strcmp(argv[1], "gamma") == 0)
+         return validation_gamma(argc-1, argv+1);
+   }
+
+   /* Bad argument: */
+   fprintf(stderr,
+      "usage: tarith [-v] [-c count] {ascii,muldiv,gamma} [args]\n");
+   fprintf(stderr, " arguments: ascii [-a (all results)] [-e error%%]\n");
+   fprintf(stderr, "            checkfp [-l max-number-chars]\n");
+   fprintf(stderr, "            muldiv\n");
+   fprintf(stderr, "            gamma -s (silent) -g (only gamma; no log)\n");
+   return 1;
+}
--- a/contrib/libtests/timepng.c
+++ b/contrib/libtests/timepng.c
@@ -0,0 +1,303 @@
+/* timepng.c
+ *
+ * Copyright (c) 2013 John Cunningham Bowler
+ *
+ * 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
+ * and license in png.h
+ *
+ * Load an arbitrary number of PNG files (from the command line, or, if there
+ * are no arguments on the command line, from stdin) then run a time test by
+ * reading each file by row.  The test does nothing with the read result and
+ * does no transforms.  The only output is a time as a floating point number of
+ * seconds with 9 decimal digits.
+ */
+#define _POSIX_C_SOURCE 199309L /* for clock_gettime */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <time.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+static int read_png(FILE *fp)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
+   png_infop info_ptr = NULL;
+   png_bytep row = NULL, display = NULL;
+
+   if (png_ptr == NULL)
+      return 0;
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      if (row != NULL) free(row);
+      if (display != NULL) free(display);
+      return 0;
+   }
+
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   png_read_info(png_ptr, info_ptr);
+
+   {
+      png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+      row = malloc(rowbytes);
+      display = malloc(rowbytes);
+
+      if (row == NULL || display == NULL)
+         png_error(png_ptr, "OOM allocating row buffers");
+
+      {
+         png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
+         int passes = png_set_interlace_handling(png_ptr);
+         int pass;
+
+         png_start_read_image(png_ptr);
+
+         for (pass = 0; pass < passes; ++pass)
+         {
+            png_uint_32 y = height;
+
+            /* NOTE: this trashes the row each time; interlace handling won't
+             * work, but this avoids memory thrashing for speed testing.
+             */
+            while (y-- > 0)
+               png_read_row(png_ptr, row, display);
+         }
+      }
+   }
+
+   /* Make sure to read to the end of the file: */
+   png_read_end(png_ptr, info_ptr);
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   free(row);
+   free(display);
+   return 1;
+}
+
+static int mytime(struct timespec *t)
+{
+   /* Do the timing using clock_gettime and the per-process timer. */
+   if (!clock_gettime(CLOCK_PROCESS_CPUTIME_ID, t))
+      return 1;
+
+   perror("CLOCK_PROCESS_CPUTIME_ID");
+   fprintf(stderr, "timepng: could not get the time\n");
+   return 0;
+}
+
+static int perform_one_test(FILE *fp, int nfiles)
+{
+   int i;
+   struct timespec before, after;
+
+   /* Clear out all errors: */
+   rewind(fp);
+
+   if (mytime(&before))
+   {
+      for (i=0; i<nfiles; ++i)
+      {
+         if (read_png(fp))
+         {
+            if (ferror(fp))
+            {
+               perror("temporary file");
+               fprintf(stderr, "file %d: error reading PNG data\n", i);
+               return 0;
+            }
+         }
+
+         else
+         {
+            perror("temporary file");
+            fprintf(stderr, "file %d: error from libpng\n", i);
+            return 0;
+         }
+      }
+   }
+
+   else
+      return 0;
+
+   if (mytime(&after))
+   {
+      /* Work out the time difference and print it - this is the only output,
+       * so flush it immediately.
+       */
+      unsigned long s = after.tv_sec - before.tv_sec;
+      long ns = after.tv_nsec - before.tv_nsec;
+
+      if (ns < 0)
+      {
+         --s;
+         ns += 1000000000;
+
+         if (ns < 0)
+         {
+            fprintf(stderr, "timepng: bad clock from kernel\n");
+            return 0;
+         }
+      }
+
+      printf("%lu.%.9ld\n", s, ns);
+      fflush(stdout);
+      if (ferror(stdout))
+      {
+         fprintf(stderr, "timepng: error writing output\n");
+         return 0;
+      }
+
+      /* Successful return */
+      return 1;
+   }
+
+   else
+      return 0;
+}
+
+static int add_one_file(FILE *fp, char *name)
+{
+   FILE *ip = fopen(name, "rb");
+
+   if (ip != NULL)
+   {
+      int ch;
+      for (;;)
+      {
+         ch = getc(ip);
+         if (ch == EOF) break;
+         putc(ch, fp);
+      }
+
+      if (ferror(ip))
+      {
+         perror(name);
+         fprintf(stderr, "%s: read error\n", name);
+         return 0;
+      }
+
+      (void)fclose(ip);
+
+      if (ferror(fp))
+      {
+         perror("temporary file");
+         fprintf(stderr, "temporary file write error\n");
+         return 0;
+      }
+   }
+
+   else
+   {
+      perror(name);
+      fprintf(stderr, "%s: open failed\n", name);
+      return 0;
+   }
+
+   return 1;
+}
+
+int main(int argc, char **argv)
+{
+   int ok = 0;
+   FILE *fp = tmpfile();
+
+   if (fp != NULL)
+   {
+      int err = 0;
+      int nfiles = 0;
+
+      if (argc > 1)
+      {
+         int i;
+
+         for (i=1; i<argc; ++i)
+         {
+            if (add_one_file(fp, argv[i]))
+               ++nfiles;
+
+            else
+            {
+               err = 1;
+               break;
+            }
+         }
+      }
+
+      else
+      {
+         char filename[FILENAME_MAX+1];
+
+         while (fgets(filename, FILENAME_MAX+1, stdin))
+         {
+            size_t len = strlen(filename);
+
+            if (filename[len-1] == '\n')
+            {
+               filename[len-1] = 0;
+               if (add_one_file(fp, filename))
+                  ++nfiles;
+
+               else
+               {
+                  err = 1;
+                  break;
+               }
+            }
+
+            else
+            {
+               fprintf(stderr, "timepng: truncated file name ...%s\n",
+                  filename+len-32);
+               err = 1;
+               break;
+            }
+         }
+
+         if (ferror(stdin))
+         {
+            fprintf(stderr, "timepng: stdin: read error\n");
+            err = 1;
+         }
+      }
+
+      if (!err)
+      {
+         if (nfiles > 0)
+            ok = perform_one_test(fp, nfiles);
+
+         else
+            fprintf(stderr, "usage: timepng {files} or ls files | timepng\n");
+      }
+
+      (void)fclose(fp);
+   }
+
+   else
+      fprintf(stderr, "timepng: could not open temporary file\n");
+
+   /* Exit code 0 on success. */
+   return ok == 0;
+}
--- a/contrib/pngminim/README
+++ b/contrib/pngminim/README
@@ -1,3 +1,4 @@
+
 This demonstrates the use of PNG_USER_CONFIG, pngusr.h and pngusr.dfa
 to build minimal decoder, encoder, and progressive reader applications.

--- a/contrib/pngminim/decoder/makefile
+++ b/contrib/pngminim/decoder/makefile
@@ -14,7 +14,8 @@ LD=$(CC)
 RM=rm -f
 COPY=cp

-CFLAGS=-DPNG_USER_CONFIG -DNO_GZCOMPRESS -DNO_GZIP -I. -O1
+CPPFLAGS=-I. -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall

 C=.c
 O=.o
@@ -81,7 +82,7 @@ OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)

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

 # dependencies

@@ -95,16 +96,16 @@ pngm2pnm$(E): $(OBJS)
 # The CPP_FLAGS setting causes pngusr.h to be included in
 # both the build of pnglibconf.h and, subsequently, when
 # building libpng itself.
-$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak\
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
 	$(PNGSRC)/scripts/pnglibconf.dfa \
 	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
 	$(RM) pnglibconf.h pnglibconf.dfn
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
-	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG"\
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
 	    DFA_XTRA="pngusr.dfa" $@

 clean:
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
 	    srcdir=$(PNGSRC) clean
 	$(RM) pngm2pnm$(O)
 	$(RM) pngm2pnm$(E)
--- a/contrib/pngminim/decoder/pngusr.dfa
+++ b/contrib/pngminim/decoder/pngusr.dfa
@@ -1,6 +1,6 @@
 # pngminim/decoder/pngusr.dfa
 #
-# Copyright (c) 2010-2011 Glenn Randers-Pehrson
+# Copyright (c) 2010-2013 Glenn Randers-Pehrson
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -37,3 +37,4 @@ option SETJMP on
 option STDIO on
 option READ_EXPAND on
 option READ_STRIP_16_TO_8 on
+option USER_LIMITS on
--- a/contrib/pngminim/decoder/pngusr.h
+++ b/contrib/pngminim/decoder/pngusr.h
@@ -1,6 +1,6 @@
 /* minrdpngconf.h: headers to make a minimal png-read-only library
 *
- * Copyright (c) 2007, 2010-2011 Glenn Randers-Pehrson
+ * Copyright (c) 2007, 2010-2013 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -18,7 +18,6 @@
 * affect the API (so are not recorded in pnglibconf.h)
 */

-#define PNG_NO_WARNINGS
 #define PNG_ALIGN_TYPE PNG_ALIGN_NONE

 #endif /* MINRDPNGCONF_H */
--- a/contrib/pngminim/encoder/README
+++ b/contrib/pngminim/encoder/README
@@ -1,6 +1,6 @@
 This demonstrates the use of PNG_USER_CONFIG and pngusr.h

-The makefile builds a minimal write-only decoder with embedded libpng
+The makefile builds a minimal write-only encoder with embedded libpng
 and zlib.

 Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
--- a/contrib/pngminim/encoder/makefile
+++ b/contrib/pngminim/encoder/makefile
@@ -14,7 +14,8 @@ LD=$(CC)
 RM=rm -f
 COPY=cp

-CFLAGS=-DPNG_USER_CONFIG -DNO_GZIP -I. -O1
+CPPFLAGS=-I. -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall

 C=.c
 O=.o
@@ -80,7 +81,7 @@ OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
 # implicit make rules -------------------------------------------------------

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

 # dependencies

@@ -94,16 +95,16 @@ pnm2pngm$(E): $(OBJS)
 # The CPP_FLAGS setting causes pngusr.h to be included in
 # both the build of pnglibconf.h and, subsequently, when
 # building libpng itself.
-$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak\
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
 	$(PNGSRC)/scripts/pnglibconf.dfa \
 	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
 	$(RM) pnglibconf.h pnglibconf.dfn
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
-	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG"\
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
 	    DFA_XTRA="pngusr.dfa" $@

 clean:
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
 	    srcdir=$(PNGSRC) clean
 	$(RM) pnm2pngm$(O)
 	$(RM) pnm2pngm$(E)
--- a/contrib/pngminim/encoder/pngusr.dfa
+++ b/contrib/pngminim/encoder/pngusr.dfa
@@ -1,6 +1,6 @@
 # pngminim/encoder/pngusr.dfa
 #
-# Copyright (c) 2010-2011 Glenn Randers-Pehrson
+# Copyright (c) 2010-2013 Glenn Randers-Pehrson
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -14,6 +14,10 @@ everything = off

 option WRITE on

+# These 2 options are required if you need to read PBM (P1 or P4) files.
+option WRITE_INVERT on
+option WRITE_PACK on
+
 # You must choose fixed or floating point arithmetic:
 # option FLOATING_POINT on

--- a/contrib/pngminim/encoder/pngusr.h
+++ b/contrib/pngminim/encoder/pngusr.h
@@ -1,6 +1,6 @@
 /* minwrpngconf.h: headers to make a minimal png-write-only library
 *
- * Copyright (c) 2007, 2010-2011 Glenn Randers-Pehrson
+ * Copyright (c) 2007, 2010-2013 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -18,7 +18,6 @@
 * affect the API (so are not recorded in pnglibconf.h)
 */

-#define PNG_NO_WARNINGS
 #define PNG_ALIGN_TYPE PNG_ALIGN_NONE

 #endif /* MINWRPNGCONF_H */
--- a/contrib/pngminim/preader/makefile
+++ b/contrib/pngminim/preader/makefile
@@ -30,7 +30,8 @@ XLIB = -L/usr/X11R6/lib -lX11
 #LIBS = $(XLIB)
 LIBS = $(XLIB) -lm                      #platforms that need libm

-CFLAGS=-DPNG_USER_CONFIG -DNO_GZCOMPRESS -DNO_GZIP -I. $(XINC) -O1
+CPPFLAGS=-I. $(XINC) -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall

 C=.c
 O=.o
@@ -96,7 +97,7 @@ OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
 # implicit make rules -------------------------------------------------------

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

 # dependencies

@@ -110,16 +111,16 @@ rpng2-x$(E): $(OBJS)
 # The CPP_FLAGS setting causes pngusr.h to be included in
 # both the build of pnglibconf.h and, subsequently, when
 # building libpng itself.
-$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak\
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
 	$(PNGSRC)/scripts/pnglibconf.dfa \
 	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
 	$(RM) pnglibconf.h pnglibconf.dfn
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
-	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG"\
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
 	    DFA_XTRA="pngusr.dfa" $@

 clean:
-	$(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
 	    srcdir=$(PNGSRC) clean
 	$(RM) rpng2-x$(O)
 	$(RM) rpng2-x$(E)
--- a/contrib/pngminim/preader/pngusr.dfa
+++ b/contrib/pngminim/preader/pngusr.dfa
@@ -1,6 +1,6 @@
 # pngminim/preader/pngusr.dfa
 #
-# Copyright (c) 2010-2011 Glenn Randers-Pehrson
+# Copyright (c) 2010-2013 Glenn Randers-Pehrson
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
--- a/contrib/pngminim/preader/pngusr.h
+++ b/contrib/pngminim/preader/pngusr.h
@@ -1,6 +1,6 @@
 /* minrdpngconf.h: headers to make a minimal png-read-only library
 *
- * Copyright (c) 2009, 2010-2011 Glenn Randers-Pehrson
+ * Copyright (c) 2009, 2010-2013 Glenn Randers-Pehrson
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
@@ -18,7 +18,6 @@
 * affect the API (so are not recorded in pnglibconf.h)
 */

-#define PNG_NO_WARNINGS
 #define PNG_ALIGN_TYPE PNG_ALIGN_NONE

 #endif /* MINPRDPNGCONF_H */
--- a/contrib/pngminus/makefile.std
+++ b/contrib/pngminus/makefile.std
@@ -8,9 +8,9 @@ LD=$(CC)
 RM=rm -f

 #PNGPATH = /usr/local
-#PNGINC = -I$(PNGPATH)/include/libpng15
-#PNGLIB = -L$(PNGPATH)/lib -lpng15
-#PNGLIBS = $(PNGPATH)/lib/libpng15.a
+#PNGINC = -I$(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/pngminus/png2pnm.bat
+++ b/contrib/pngminus/png2pnm.bat
--- a/contrib/pngminus/png2pnm.c
+++ b/contrib/pngminus/png2pnm.c
@@ -18,6 +18,7 @@
 #include <mem.h>
 #include <fcntl.h>
 #endif
+#include <zlib.h>

 #ifndef BOOL
 #define BOOL unsigned char
@@ -51,7 +52,8 @@

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

 /*
 *  main
@@ -84,7 +86,8 @@ int main(int argc, char *argv[])
          if ((fp_al = fopen (argv[argi], "wb")) == NULL)
          {
            fprintf (stderr, "PNM2PNG\n");
-            fprintf (stderr, "Error:  can not create alpha-channel file %s\n", argv[argi]);
+            fprintf (stderr, "Error:  can not create alpha-channel file %s\n",
+               argv[argi]);
            exit (1);
          }
          break;
@@ -175,9 +178,11 @@ void usage()
  fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
  fprintf (stderr, "   or:  ... | png2pnm [options]\n");
  fprintf (stderr, "Options:\n");
-  fprintf (stderr, "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
+  fprintf (stderr,
+     "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
  fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
+  fprintf (stderr,
+     "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
  fprintf (stderr, "   -h | -?  print this help-information\n");
 }

@@ -185,7 +190,8 @@ void usage()
 *  png2pnm
 */

-BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha)
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
+    volatile BOOL raw, BOOL alpha)
 {
  png_struct    *png_ptr = NULL;
  png_info        *info_ptr = NULL;
@@ -217,7 +223,7 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a

  /* create png and info structures */

-  png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING,
+  png_ptr = png_create_read_struct (png_get_libpng_ver(NULL),
    NULL, NULL, NULL);
  if (!png_ptr)
    return FALSE;   /* out of memory */
@@ -314,12 +320,14 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
  /* row_bytes is the width x number of channels x (bit-depth / 8) */
  row_bytes = png_get_rowbytes (png_ptr, info_ptr);

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

-  if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+  if ((row_pointers = (png_byte **)
+     malloc (height * sizeof (png_bytep))) == NULL)
  {
    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
    free (png_pixels);
@@ -328,7 +336,7 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
  }

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

  /* now we can go ahead and just read the whole image */
@@ -371,9 +379,9 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
  /* write data to PNM file */
  pix_ptr = png_pixels;

-  for (row = 0; row < height; row++)
+  for (row = 0; row < (int) height; row++)
  {
-    for (col = 0; col < width; col++)
+    for (col = 0; col < (int) width; col++)
    {
      for (i = 0; i < (channels - alpha_present); i++)
      {
--- a/contrib/pngminus/png2pnm.sh
+++ b/contrib/pngminus/png2pnm.sh
--- a/contrib/pngminus/pngminus.bat
+++ b/contrib/pngminus/pngminus.bat
--- a/contrib/pngminus/pngminus.sh
+++ b/contrib/pngminus/pngminus.sh
--- a/contrib/pngminus/pnm2png.bat
+++ b/contrib/pngminus/pnm2png.bat
--- a/contrib/pngminus/pnm2png.c
+++ b/contrib/pngminus/pnm2png.c
@@ -18,6 +18,7 @@
 #include <mem.h>
 #include <fcntl.h>
 #endif
+#include <zlib.h>

 #ifndef BOOL
 #define BOOL unsigned char
@@ -49,7 +50,8 @@

 int  main (int argc, char *argv[]);
 void usage ();
-BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha);
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
+    BOOL alpha);
 void get_token(FILE *pnm_file, char *token);
 png_uint_32 get_data (FILE *pnm_file, int depth);
 png_uint_32 get_value (FILE *pnm_file, int depth);
@@ -175,7 +177,8 @@ void usage()
  fprintf (stderr, "   or:  ... | pnm2png [options]\n");
  fprintf (stderr, "Options:\n");
  fprintf (stderr, "   -i[nterlace]   write png-file with interlacing on\n");
-  fprintf (stderr, "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
+  fprintf (stderr,
+      "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
  fprintf (stderr, "   -h | -?  print this help-information\n");
 }

@@ -183,29 +186,36 @@ void usage()
 *  pnm2png
 */

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

  char          type_token[16];
  char          width_token[16];
  char          height_token[16];
  char          maxval_token[16];
-  int           color_type;
-  png_uint_32   width, alpha_width;
-  png_uint_32   height, alpha_height;
+  volatile int           color_type;
+  unsigned long   ul_width=0, ul_alpha_width=0;
+  unsigned long   ul_height=0, ul_alpha_height=0;
+  unsigned long   ul_maxval=0;
+  volatile png_uint_32   width, height;
+  volatile png_uint_32   alpha_width, alpha_height;
  png_uint_32   maxval;
-  int           bit_depth = 0;
+  volatile int           bit_depth = 0;
  int           channels;
  int           alpha_depth = 0;
  int           alpha_present;
  int           row, col;
  BOOL          raw, alpha_raw = FALSE;
+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+  BOOL          packed_bitmap = FALSE;
+#endif
  png_uint_32   tmp16;
  int           i;

@@ -218,20 +228,36 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  }
  else if ((type_token[1] == '1') || (type_token[1] == '4'))
  {
+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
    raw = (type_token[1] == '4');
    color_type = PNG_COLOR_TYPE_GRAY;
+    get_token(pnm_file, width_token);
+    sscanf (width_token, "%lu", &ul_width);
+    width = (png_uint_32) ul_width;
+    get_token(pnm_file, height_token);
+    sscanf (height_token, "%lu", &ul_height);
+    height = (png_uint_32) ul_height;
    bit_depth = 1;
+    packed_bitmap = TRUE;
+#else
+    fprintf (stderr, "PNM2PNG built without PNG_WRITE_INVERT_SUPPORTED and \n");
+    fprintf (stderr, "PNG_WRITE_PACK_SUPPORTED can't read PBM (P1,P4) files\n");
+#endif
  }
  else if ((type_token[1] == '2') || (type_token[1] == '5'))
  {
    raw = (type_token[1] == '5');
    color_type = PNG_COLOR_TYPE_GRAY;
    get_token(pnm_file, width_token);
-    sscanf (width_token, "%lu", &width);
+    sscanf (width_token, "%lu", &ul_width);
+    width = (png_uint_32) ul_width;
    get_token(pnm_file, height_token);
-    sscanf (height_token, "%lu", &height);
+    sscanf (height_token, "%lu", &ul_height);
+    height = (png_uint_32) ul_height;
    get_token(pnm_file, maxval_token);
-    sscanf (maxval_token, "%lu", &maxval);
+    sscanf (maxval_token, "%lu", &ul_maxval);
+    maxval = (png_uint_32) ul_maxval;
+
    if (maxval <= 1)
      bit_depth = 1;
    else if (maxval <= 3)
@@ -248,11 +274,14 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
    raw = (type_token[1] == '6');
    color_type = PNG_COLOR_TYPE_RGB;
    get_token(pnm_file, width_token);
-    sscanf (width_token, "%lu", &width);
+    sscanf (width_token, "%lu", &ul_width);
+    width = (png_uint_32) ul_width;
    get_token(pnm_file, height_token);
-    sscanf (height_token, "%lu", &height);
+    sscanf (height_token, "%lu", &ul_height);
+    height = (png_uint_32) ul_height;
    get_token(pnm_file, maxval_token);
-    sscanf (maxval_token, "%lu", &maxval);
+    sscanf (maxval_token, "%lu", &ul_maxval);
+    maxval = (png_uint_32) ul_maxval;
    if (maxval <= 1)
      bit_depth = 1;
    else if (maxval <= 3)
@@ -287,15 +316,18 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
    {
      alpha_raw = (type_token[1] == '5');
      get_token(alpha_file, width_token);
-      sscanf (width_token, "%lu", &alpha_width);
+      sscanf (width_token, "%lu", &ul_alpha_width);
+      alpha_width=(png_uint_32) ul_alpha_width;
      if (alpha_width != width)
        return FALSE;
      get_token(alpha_file, height_token);
-      sscanf (height_token, "%lu", &alpha_height);
+      sscanf (height_token, "%lu", &ul_alpha_height);
+      alpha_height = (png_uint_32) ul_alpha_height;
      if (alpha_height != height)
        return FALSE;
      get_token(alpha_file, maxval_token);
-      sscanf (maxval_token, "%lu", &maxval);
+      sscanf (maxval_token, "%lu", &ul_maxval);
+      maxval = (png_uint_32) ul_maxval;
      if (maxval <= 1)
        alpha_depth = 1;
      else if (maxval <= 3)
@@ -329,56 +361,72 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,

  alpha_present = (channels - 1) % 2;

-  /* row_bytes is the width x number of channels x (bit-depth / 8) */
-  row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);
+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+  if (packed_bitmap)
+    /* row data is as many bytes as can fit width x channels x bit_depth */
+    row_bytes = (width * channels * bit_depth + 7) / 8;
+  else
+#endif
+    /* row_bytes is the width x number of channels x (bit-depth / 8) */
+    row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);

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

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

-  for (row = 0; row < height; row++)
+  for (row = 0; row < (int) height; row++)
  {
-    for (col = 0; col < width; col++)
+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+    if (packed_bitmap) {
+      for (i = 0; i < (int) row_bytes; i++)
+        /* png supports this format natively so no conversion is needed */
+        *pix_ptr++ = get_data (pnm_file, 8);
+    } else
+#endif
    {
-      for (i = 0; i < (channels - alpha_present); i++)
+      for (col = 0; col < (int) width; col++)
      {
-        if (raw)
-          *pix_ptr++ = get_data (pnm_file, bit_depth);
-        else
-          if (bit_depth <= 8)
-            *pix_ptr++ = get_value (pnm_file, bit_depth);
+        for (i = 0; i < (channels - alpha_present); i++)
+        {
+          if (raw)
+            *pix_ptr++ = get_data (pnm_file, bit_depth);
          else
-          {
-            tmp16 = get_value (pnm_file, bit_depth);
-            *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
-            pix_ptr++;
-            *pix_ptr = (png_byte) (tmp16 & 0xFF);
-            pix_ptr++;
-          }
-      }
+            if (bit_depth <= 8)
+              *pix_ptr++ = get_value (pnm_file, bit_depth);
+            else
+            {
+              tmp16 = get_value (pnm_file, bit_depth);
+              *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
+              pix_ptr++;
+              *pix_ptr = (png_byte) (tmp16 & 0xFF);
+              pix_ptr++;
+            }
+        }

-      if (alpha) /* read alpha-channel from pgm file */
-      {
-        if (alpha_raw)
-          *pix_ptr++ = get_data (alpha_file, alpha_depth);
-        else
-          if (alpha_depth <= 8)
-            *pix_ptr++ = get_value (alpha_file, bit_depth);
+        if (alpha) /* read alpha-channel from pgm file */
+        {
+          if (alpha_raw)
+            *pix_ptr++ = get_data (alpha_file, alpha_depth);
          else
-          {
-            tmp16 = get_value (alpha_file, bit_depth);
-            *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
-            *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
-          }
-      } /* if alpha */
-
+            if (alpha_depth <= 8)
+              *pix_ptr++ = get_value (alpha_file, bit_depth);
+            else
+            {
+              tmp16 = get_value (alpha_file, bit_depth);
+              *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
+              *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
+            }
+        } /* if alpha */
+      } /* if packed_bitmap */
    } /* end for col */
  } /* end for row */

  /* prepare the standard PNG structures */
-  png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+  png_ptr = png_create_write_struct (png_get_libpng_ver(NULL), NULL, NULL,
+      NULL);
  if (!png_ptr)
  {
    return FALSE;
@@ -390,6 +438,14 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
    return FALSE;
  }

+#if defined(PNG_WRITE_INVERT_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+  if (packed_bitmap == TRUE)
+  {
+    png_set_packing (png_ptr);
+    png_set_invert_mono (png_ptr);
+  }
+#endif
+
  /* setjmp() must be called in every function that calls a PNG-reading libpng function */
  if (setjmp (png_jmpbuf(png_ptr)))
  {
@@ -411,7 +467,8 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  /* if needed we will allocate memory for an new array of row-pointers */
  if (row_pointers == (unsigned char**) NULL)
  {
-    if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+    if ((row_pointers = (png_byte **)
+        malloc (height * sizeof (png_bytep))) == NULL)
    {
      png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
      return FALSE;
@@ -419,13 +476,13 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
  }

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

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

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

  /* clean up after the write, and free any memory allocated */
@@ -446,19 +503,32 @@ BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace,
 void get_token(FILE *pnm_file, char *token)
 {
  int i = 0;
+  int ret;

-  /* remove white-space */
+  /* remove white-space and comment lines */
  do
  {
-    token[i] = (unsigned char) fgetc (pnm_file);
+    ret = fgetc(pnm_file);
+    if (ret == '#') {
+      /* the rest of this line is a comment */
+      do
+      {
+        ret = fgetc(pnm_file);
+      }
+      while ((ret != '\n') && (ret != '\r') && (ret != EOF));
+    }
+    if (ret == EOF) break;
+    token[i] = (unsigned char) ret;
  }
  while ((token[i] == '\n') || (token[i] == '\r') || (token[i] == ' '));

  /* read string */
  do
  {
+    ret = fgetc(pnm_file);
+    if (ret == EOF) break;
    i++;
-    token[i] = (unsigned char) fgetc (pnm_file);
+    token[i] = (unsigned char) ret;
  }
  while ((token[i] != '\n') && (token[i] != '\r') && (token[i] != ' '));

@@ -510,6 +580,7 @@ png_uint_32 get_value (FILE *pnm_file, int depth)
 {
  static png_uint_32 mask = 0;
  png_byte token[16];
+  unsigned long ul_ret_value;
  png_uint_32 ret_value;
  int i = 0;

@@ -518,7 +589,8 @@ png_uint_32 get_value (FILE *pnm_file, int depth)
      mask = (mask << 1) | 0x01;

  get_token (pnm_file, (char *) token);
-  sscanf ((const char *) token, "%lu", &ret_value);
+  sscanf ((const char *) token, "%lu", &ul_ret_value);
+  ret_value = (png_uint_32) ul_ret_value;

  ret_value &= mask;

--- a/contrib/pngminus/pnm2png.sh
+++ b/contrib/pngminus/pnm2png.sh
--- a/contrib/pngsuite/README
+++ b/contrib/pngsuite/README
@@ -1,7 +1,8 @@

 pngsuite
 --------
-(c) Willem van Schaik, 1999, 2011
+(c) Willem van Schaik, 1999, 2011, 2012
+Two images are by Glenn Randers-Pehrson, 2012

 Permission to use, copy, modify, and distribute these images for any
 purpose and without fee is hereby granted.
@@ -38,6 +39,8 @@ can use them to test the proper functioning of PNG software.
    basn6a08.png   8-bit RGBA
    basn6a16.png  16-bit RGBA

+    ftbbn0g01.png  1-bit grayscale, black bKGD
+    ftbbn0g02.png  2-bit grayscale, black bKGD
    ftbbn0g04.png  4-bit grayscale, black bKGD
    ftbbn2c16.png 16-bit truecolor, black bKGD
    ftbbn3p08.png  8-bit paletted, black bKGD
--- a/contrib/pngsuite/ftbbn0g01.png
+++ b/contrib/pngsuite/ftbbn0g01.png
--- a/contrib/pngsuite/ftbbn0g02.png
+++ b/contrib/pngsuite/ftbbn0g02.png
--- a/contrib/pngsuite/ftbbn0g04.png
+++ b/contrib/pngsuite/ftbbn0g04.png
--- a/contrib/pngsuite/ftbwn0g16.png
+++ b/contrib/pngsuite/ftbwn0g16.png
--- a/contrib/pngsuite/ftp0n0g08.png
+++ b/contrib/pngsuite/ftp0n0g08.png
--- a/contrib/tools/README.txt
+++ b/contrib/tools/README.txt
@@ -0,0 +1,26 @@
+This directory (contrib/tools) contains tools used by the authors of libpng.
+
+Code and data placed in this directory is not required to build libpng,
+however the code in this directory has been used to generate data or code in
+the body of the libpng source.  The source code identifies where this has
+been done.  Code in this directory may not compile on all operating systems
+that libpng supports.
+
+NO COPYRIGHT RIGHTS ARE CLAIMED TO ANY OF THE FILES IN THIS DIRECTORY.
+
+To the extent possible under law, the authors have waived all copyright and
+related or neighboring rights to this work.  This work is published from:
+United States.
+
+The files may be used freely in any way.
+
+The source code and comments in this directory are the original work of the
+people named below.  No other person or organization has made contributions to
+the work in this directory.
+
+ORIGINAL AUTHORS
+    The following people have contributed to the code in this directory.  None
+    of the people below claim any rights with regard to the contents of this
+    directory.
+
+    John Bowler <jbowler@acm.org>
--- a/contrib/tools/checksum-icc.c
+++ b/contrib/tools/checksum-icc.c
@@ -0,0 +1,102 @@
+/* checksum-icc.c
+ *
+ * Copyright (c) 2013 John Cunningham Bowler
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Generate crc32 and adler32 checksums of the given input files, used to
+ * generate check-codes for use when matching ICC profiles within libpng.
+ */
+#include <stdio.h>
+
+#include <zlib.h>
+
+static int
+read_one_file(FILE *ip, const char *name)
+{
+   uLong length = 0;
+   uLong a32 = adler32(0, NULL, 0);
+   uLong c32 = crc32(0, NULL, 0);
+   Byte header[132];
+
+   for (;;)
+   {
+      int ch = getc(ip);
+      Byte b;
+
+      if (ch == EOF) break;
+
+      b = (Byte)ch;
+
+      if (length < sizeof header)
+         header[length] = b;
+
+      ++length;
+      a32 = adler32(a32, &b, 1);
+      c32 = crc32(c32, &b, 1);
+   }
+
+   if (ferror(ip))
+      return 0;
+
+   /* Success */
+   printf("PNG_ICC_CHECKSUM(0x%8.8lx, 0x%8.8lx,\n   PNG_MD5("
+      "0x%2.2x%2.2x%2.2x%2.2x, 0x%2.2x%2.2x%2.2x%2.2x, 0x%2.2x%2.2x%2.2x%2.2x,"
+      " 0x%2.2x%2.2x%2.2x%2.2x), %d,\n"
+      "   \"%4.4d/%2.2d/%2.2d %2.2d:%2.2d:%2.2d\", %lu, \"%s\")\n",
+      (unsigned long)a32, (unsigned long)c32,
+      header[84], header[85], header[86], header[87],
+      header[88], header[89], header[90], header[91],
+      header[92], header[93], header[94], header[95],
+      header[96], header[97], header[98], header[99],
+#     define u16(x) (header[x] * 256 + header[x+1])
+#     define u32(x) (u16(x) * 65536 + u16(x+2))
+      u32(64), u16(24), u16(26), u16(28), u16(30), u16(32), u16(34),
+      (unsigned long)length, name);
+
+   return 1;
+}
+
+int main(int argc, char **argv)
+{
+   int err = 0;
+
+   printf("/* adler32, crc32, MD5[16], intent, date, length, file-name */\n");
+
+   if (argc > 1)
+   {
+      int i;
+
+      for (i=1; i<argc; ++i)
+      {
+         FILE *ip = fopen(argv[i], "rb");
+
+         if (ip == NULL || !read_one_file(ip, argv[i]))
+         {
+            err = 1;
+            perror(argv[i]);
+            fprintf(stderr, "%s: read error\n", argv[i]);
+            printf("/* ERROR: %s */\n", argv[i]);
+         }
+
+         (void)fclose(ip);
+      }
+   }
+
+   else
+   {
+      if (!read_one_file(stdin, "-"))
+      {
+         err = 1;
+         perror("stdin");
+         fprintf(stderr, "stdin: read error\n");
+         printf("/* ERROR: stdin */\n");
+      }
+   }
+
+   return err;
+}
--- a/contrib/tools/chkfmt
+++ b/contrib/tools/chkfmt
--- a/contrib/tools/cvtcolor.c
+++ b/contrib/tools/cvtcolor.c
@@ -0,0 +1,188 @@
+/*-
+ * convert.c
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2013.
+ * 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.
+ *
+ * Convert 8-bit sRGB or 16-bit linear values to another format.
+ */
+#define _ISOC99_SOURCE 1
+
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+
+#include <fenv.h>
+
+#include "sRGB.h"
+
+static void
+usage(const char *prog)
+{
+   fprintf(stderr,
+      "%s: usage: %s [-linear|-sRGB] [-gray|-color] component{1,4}\n",
+      prog, prog);
+   exit(1);
+}
+
+unsigned long
+component(const char *prog, const char *arg, int issRGB)
+{
+   char *ep;
+   unsigned long c = strtoul(arg, &ep, 0);
+
+   if (ep <= arg || *ep || c > 65535 || (issRGB && c > 255))
+   {
+      fprintf(stderr, "%s: %s: invalid component value (%lu)\n", prog, arg, c);
+      usage(prog);
+   }
+
+   return c;
+}
+
+int
+main(int argc, const char **argv)
+{
+   const char *prog = *argv++;
+   int to_linear = 0, to_gray = 0, to_color = 0;
+   int channels = 0;
+   double c[4];
+
+   /* FE_TONEAREST is the IEEE754 round to nearest, preferring even, mode; i.e.
+    * everything rounds to the nearest value except that '.5' rounds to the
+    * nearest even value.
+    */
+   fesetround(FE_TONEAREST);
+
+   c[3] = c[2] = c[1] = c[0] = 0;
+
+   while (--argc > 0 && **argv == '-')
+   {
+      const char *arg = 1+*argv++;
+
+      if (strcmp(arg, "sRGB") == 0)
+         to_linear = 0;
+
+      else if (strcmp(arg, "linear") == 0)
+         to_linear = 1;
+
+      else if (strcmp(arg, "gray") == 0)
+         to_gray = 1, to_color = 0;
+
+      else if (strcmp(arg, "color") == 0)
+         to_gray = 0, to_color = 1;
+
+      else
+         usage(prog);
+   }
+
+   switch (argc)
+   {
+      default:
+         usage(prog);
+         break;
+
+      case 4:
+         c[3] = component(prog, argv[3], to_linear);
+         ++channels;
+      case 3:
+         c[2] = component(prog, argv[2], to_linear);
+         ++channels;
+      case 2:
+         c[1] = component(prog, argv[1], to_linear);
+         ++channels;
+      case 1:
+         c[0] = component(prog, argv[0], to_linear);
+         ++channels;
+         break;
+      }
+
+   if (to_linear)
+   {
+      int i;
+      int components = channels;
+
+      if ((components & 1) == 0)
+         --components;
+
+      for (i=0; i<components; ++i) c[i] = linear_from_sRGB(c[i] / 255);
+      if (components < channels)
+         c[components] = c[components] / 255;
+   }
+
+   else
+   {
+      int i;
+      for (i=0; i<4; ++i) c[i] /= 65535;
+
+      if ((channels & 1) == 0)
+      {
+         double alpha = c[channels-1];
+
+         if (alpha > 0)
+            for (i=0; i<channels-1; ++i) c[i] /= alpha;
+         else
+            for (i=0; i<channels-1; ++i) c[i] = 1;
+      }
+   }
+
+   if (to_gray)
+   {
+      if (channels < 3)
+      {
+         fprintf(stderr, "%s: too few channels (%d) for -gray\n",
+            prog, channels);
+         usage(prog);
+      }
+
+      c[0] = YfromRGB(c[0], c[1], c[2]);
+      channels -= 2;
+   }
+
+   if (to_color)
+   {
+      if (channels > 2)
+      {
+         fprintf(stderr, "%s: too many channels (%d) for -color\n",
+            prog, channels);
+         usage(prog);
+      }
+
+      c[3] = c[1]; /* alpha, if present */
+      c[2] = c[1] = c[0];
+   }
+
+   if (to_linear)
+   {
+      int i;
+      if ((channels & 1) == 0)
+      {
+         double alpha = c[channels-1];
+         for (i=0; i<channels-1; ++i) c[i] *= alpha;
+      }
+
+      for (i=0; i<channels; ++i) c[i] = nearbyint(c[i] * 65535);
+   }
+
+   else /* to sRGB */
+   {
+      int i = (channels+1)&~1;
+      while (--i >= 0)
+         c[i] = sRGB_from_linear(c[i]);
+
+      for (i=0; i<channels; ++i) c[i] = nearbyint(c[i] * 255);
+   }
+
+   {
+      int i;
+      for (i=0; i<channels; ++i) printf(" %g", c[i]);
+   }
+   printf("\n");
+
+   return 0;
+}
--- a/contrib/tools/genpng.c
+++ b/contrib/tools/genpng.c
@@ -0,0 +1,867 @@
+/*- genpng
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2015.
+ * 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.
+ *
+ * Generate a PNG with an alpha channel, correctly.
+ *
+ * This is a test case generator; the resultant PNG files are only of interest
+ * to those of us who care about whether the edges of circles are green, red,
+ * or yellow.
+ *
+ * The program generates an RGB+Alpha PNG of a given size containing the given
+ * shapes on a transparent background:
+ *
+ *  genpng width height { shape }
+ *    shape ::= color width shape x1 y1 x2 y2
+ *
+ * 'color' is:
+ *
+ *  black white red green yellow blue brown purple pink orange gray cyan
+ *
+ * The point is to have colors that are linguistically meaningful plus that old
+ * bugbear of the department store dress murders, Cyan, the only color we argue
+ * about.
+ *
+ * 'shape' is:
+ *
+ *  circle: an ellipse
+ *  square: a rectangle
+ *  line: a straight line
+ *
+ * Each shape is followed by four numbers, these are two points in the output
+ * coordinate space (as real numbers) which describe the circle, square, or
+ * line.  The shape is filled if it is preceded by 'filled' (not valid for
+ * 'line') or is drawn with a line, in which case the width of the line must
+ * precede the shape.
+ *
+ * The whole set of information can be repeated as many times as desired:
+ *
+ *    shape ::= color width shape x1 y1 x2 y2
+ *
+ *    color ::= black|white|red|green|yellow|blue
+ *    color ::= brown|purple|pink|orange|gray|cyan
+ *    width ::= filled
+ *    width ::= <number>
+ *    shape ::= circle|square|line
+ *    x1    ::= <number>
+ *    x2    ::= <number>
+ *    y1    ::= <number>
+ *    y2    ::= <number>
+ *
+ * The output PNG is generated by down-sampling a 4x supersampled image using
+ * a bi-cubic filter.  The bi-cubic has a 2 (output) pixel width, so an 8x8
+ * array of super-sampled points contribute to each output pixel.  The value of
+ * a super-sampled point is found using an unfiltered, aliased, infinite
+ * precision image: Each shape from the last to the first is checked to see if
+ * the point is in the drawn area and, if it is, the color of the point is the
+ * color of the shape and the alpha is 1, if not the previous shape is checked.
+ *
+ * This is an aliased algorithm because no filtering is done; a point is either
+ * inside or outside each shape and 'close' points do not contribute to the
+ * sample.  The down-sampling is relied on to correct the error of not using
+ * a filter.
+ *
+ * The line end-caps are 'flat'; they go through the points.  The square line
+ * joins are mitres; the outside of the lines are continued to the point of
+ * intersection.
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <math.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation:
+ */
+#include "../../png.h"
+
+#if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
+
+static const struct color
+{
+   const char *name;
+   double      red;
+   double      green;
+   double      blue;
+} colors[] =
+/* color ::= black|white|red|green|yellow|blue
+ * color ::= brown|purple|pink|orange|gray|cyan
+ */
+{
+   { "black",   0,    0,  0 },
+   { "white",   1,    1,  1 },
+   { "red",     1,    0,  0 },
+   { "green",   0,    1,  0 },
+   { "yellow",  1,    1,  0 },
+   { "blue",    0,    0,  1 },
+   { "brown",  .5, .125,  0 },
+   { "purple",  1,    0,  1 },
+   { "pink",    1,   .5, .5 },
+   { "orange",  1,   .5,  0 },
+   { "gray",    0,   .5, .5 },
+   { "cyan",    0,    1,  1 }
+};
+#define color_count ((sizeof colors)/(sizeof colors[0]))
+
+static const struct color *
+color_of(const char *arg)
+{
+   int icolor = color_count;
+
+   while (--icolor >= 0)
+   {
+      if (strcmp(colors[icolor].name, arg) == 0)
+         return colors+icolor;
+   }
+
+   fprintf(stderr, "genpng: invalid color %s\n", arg);
+   exit(1);
+}
+
+static double
+width_of(const char *arg)
+{
+   if (strcmp(arg, "filled") == 0)
+      return 0;
+
+   else
+   {
+      char *ep = NULL;
+      double w = strtod(arg, &ep);
+
+      if (ep != NULL && *ep == 0 && w > 0)
+         return w;
+   }
+
+   fprintf(stderr, "genpng: invalid line width %s\n", arg);
+   exit(1);
+}
+
+static double
+coordinate_of(const char *arg)
+{
+   char *ep = NULL;
+   double w = strtod(arg, &ep);
+
+   if (ep != NULL && *ep == 0)
+      return w;
+
+   fprintf(stderr, "genpng: invalid coordinate value %s\n", arg);
+   exit(1);
+}
+
+struct arg; /* forward declaration */
+
+typedef int (*shape_fn_ptr)(const struct arg *arg, double x, double y);
+   /* A function to determine if (x,y) is inside the shape.
+    *
+    * There are two implementations:
+    *
+    *    inside_fn: returns true if the point is inside
+    *    check_fn:  returns;
+    *       -1: the point is outside the shape by more than the filter width (2)
+    *        0: the point may be inside the shape
+    *       +1: the point is inside the shape by more than the filter width
+    */
+#define OUTSIDE (-1)
+#define INSIDE  (1)
+
+struct arg
+{
+   const struct color *color;
+   shape_fn_ptr        inside_fn;
+   shape_fn_ptr        check_fn;
+   double              width; /* line width, 0 for 'filled' */
+   double              x1, y1, x2, y2;
+};
+
+/* IMPLEMENTATION NOTE:
+ *
+ * We want the contribution of each shape to the sample corresponding to each
+ * pixel.  This could be obtained by super sampling the image to infinite
+ * dimensions, finding each point within the shape and assigning that a value
+ * '1' while leaving every point outside the shape with value '0' then
+ * downsampling to the image size with sinc; computationally very expensive.
+ *
+ * Approximations are as follows:
+ *
+ * 1) If the pixel coordinate is within the shape assume the sample has the
+ *    shape color and is opaque, else assume there is no contribution from
+ *    the shape.
+ *
+ *    This is the equivalent of aliased rendering or resampling an image with
+ *    a block filter.  The maximum error in the calculated alpha (which will
+ *    always be 0 or 1) is 0.5.
+ *
+ * 2) If the shape is within a square of size 1x1 centered on the pixel assume
+ *    that the shape obscures an amount of the pixel equal to its area within
+ *    that square.
+ *
+ *    This is the equivalent of 'pixel coverage' alpha calculation or resampling
+ *    an image with a bi-linear filter.  The maximum error is over 0.2, but the
+ *    results are often acceptable.
+ *
+ *    This can be approximated by applying (1) to a super-sampled image then
+ *    downsampling with a bi-linear filter.  The error in the super-sampled
+ *    image is 0.5 per sample, but the resampling reduces this.
+ *
+ * 3) Use a better filter with a super-sampled image; in the limit this is the
+ *    sinc() approach.
+ *
+ * 4) Do the geometric calculation; a bivariate definite integral across the
+ *    shape, unfortunately this means evaluating Si(x), the integral of sinc(x),
+ *    which is still a lot of math.
+ *
+ * This code uses approach (3) with a bi-cubic filter and 8x super-sampling
+ * and method (1) for the super-samples.  This means that the sample is either
+ * 0 or 1, depending on whether the sub-pixel is within or outside the shape.
+ * The bi-cubic weights are also fixed and the 16 required weights are
+ * pre-computed here (note that the 'scale' setting will need to be changed if
+ * 'super' is increased).
+ *
+ * The code also calculates a sum to the edge of the filter. This is not
+ * currently used by could be used to optimize the calculation.
+ */
+#if 0 /* bc code */
+scale=10
+super=8
+define bicubic(x) {
+   if (x <= 1) return (1.5*x - 2.5)*x*x + 1;
+   if (x <  2) return (((2.5 - 0.5*x)*x - 4)*x + 2);
+   return 0;
+}
+define sum(x) {
+   auto s;
+   s = 0;
+   while (x < 2*super) {
+      s = s + bicubic(x/super);
+      x = x + 1;
+   }
+   return s;
+}
+define results(x) {
+   auto b, s;
+   b = bicubic(x/super);
+   s = sum(x);
+
+   print "   /*", x, "*/ { ", b, ", ", s, " }";
+   return 1;
+}
+x=0
+while (x<2*super) {
+   x = x + results(x)
+   if (x < 2*super) print ","
+   print "\n"
+}
+quit
+#endif
+
+#define BICUBIC1(x) /*     |x| <= 1 */ ((1.5*(x)* - 2.5)*(x)*(x) + 1)
+#define BICUBIC2(x) /* 1 < |x| <  2 */ (((2.5 - 0.5*(x))*(x) - 4)*(x) + 2)
+#define FILTER_WEIGHT 9 /* Twice the first sum below */
+#define FILTER_WIDTH  2 /* Actually half the width; -2..+2 */
+#define FILTER_STEPS  8 /* steps per filter unit */
+static const double
+bicubic[16][2] =
+{
+   /* These numbers are exact; the weight for the filter is 1/9, but this
+    * would make the numbers inexact, so it is not included here.
+    */
+   /*          bicubic      sum        */
+   /* 0*/ { 1.0000000000, 4.5000000000 },
+   /* 1*/ {  .9638671875, 3.5000000000 },
+   /* 2*/ {  .8671875000, 2.5361328125 },
+   /* 3*/ {  .7275390625, 1.6689453125 },
+   /* 4*/ {  .5625000000,  .9414062500 },
+   /* 5*/ {  .3896484375,  .3789062500 },
+   /* 6*/ {  .2265625000, -.0107421875 },
+   /* 7*/ {  .0908203125, -.2373046875 },
+   /* 8*/ {            0, -.3281250000 },
+   /* 9*/ { -.0478515625, -.3281250000 },
+   /*10*/ { -.0703125000, -.2802734375 },
+   /*11*/ { -.0732421875, -.2099609375 },
+   /*12*/ { -.0625000000, -.1367187500 },
+   /*13*/ { -.0439453125, -.0742187500 },
+   /*14*/ { -.0234375000, -.0302734375 },
+   /*15*/ { -.0068359375, -.0068359375 }
+};
+
+static double
+alpha_calc(const struct arg *arg, double x, double y)
+{
+   /* For [x-2..x+2],[y-2,y+2] calculate the weighted bicubic given a function
+    * which tells us whether a point is inside or outside the shape.  First
+    * check if we need to do this at all:
+    */
+   switch (arg->check_fn(arg, x, y))
+   {
+      case OUTSIDE:
+         return 0; /* all samples outside the shape */
+
+      case INSIDE:
+         return 1; /* all samples inside the shape */
+
+      default:
+      {
+         int dy;
+         double alpha = 0;
+
+#        define FILTER_D (FILTER_WIDTH*FILTER_STEPS-1)
+         for (dy=-FILTER_D; dy<=FILTER_D; ++dy)
+         {
+            double wy = bicubic[abs(dy)][0];
+
+            if (wy != 0)
+            {
+               double alphay = 0;
+               int dx;
+
+               for (dx=-FILTER_D; dx<=FILTER_D; ++dx)
+               {
+                  double wx = bicubic[abs(dx)][0];
+
+                  if (wx != 0 && arg->inside_fn(arg, x+dx/16, y+dy/16)) 
+                     alphay += wx;
+               }
+
+               alpha += wy * alphay;
+            }
+         }
+
+         /* This needs to be weighted for each dimension: */
+         return alpha / (FILTER_WEIGHT*FILTER_WEIGHT);
+      }
+   }
+}
+
+/* These are the shape functions. */
+/* "square",
+ * { inside_square_filled, check_square_filled },
+ * { inside_square, check_square }
+ */
+static int
+square_check(double x, double y, double x1, double y1, double x2, double y2)
+   /* Is x,y inside the square (x1,y1)..(x2,y2)? */
+{
+   /* Do a modified Cohen-Sutherland on one point, bit patterns that indicate
+    * 'outside' are:
+    *
+    *   x<x1 | x<y1 | x<x2 | x<y2
+    *    0      x      0      x     To the right
+    *    1      x      1      x     To the left
+    *    x      0      x      0     Below
+    *    x      1      x      1     Above
+    *
+    * So 'inside' is (x<x1) != (x<x2) && (y<y1) != (y<y2);
+    */
+   return ((x<x1) ^ (x<x2)) & ((y<y1) ^ (y<y2));
+}
+
+static int
+inside_square_filled(const struct arg *arg, double x, double y)
+{
+   return square_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2);
+}
+
+static int
+square_check_line(const struct arg *arg, double x, double y, double w)
+   /* Check for a point being inside the boundaries implied by the given arg
+    * and assuming a width 2*w each side of the boundaries.  This returns the
+    * 'check' INSIDE/OUTSIDE/0 result but note the semantics:
+    *
+    *          +--------------+
+    *          |              |   OUTSIDE
+    *          |   INSIDE     |
+    *          |              |
+    *          +--------------+
+    *
+    * And '0' means within the line boundaries.
+    */
+{
+   double cx = (arg->x1+arg->x2)/2;
+   double wx = fabs(arg->x1-arg->x2)/2;
+   double cy = (arg->y1+arg->y2)/2;
+   double wy = fabs(arg->y1-arg->y2)/2;
+
+   if (square_check(x, y, cx-wx-w, cy-wy-w, cx+wx+w, cy+wy+w))
+   {
+      /* Inside, but maybe too far; check for the redundant case where
+       * the lines overlap:
+       */
+      wx -= w;
+      wy -= w;
+      if (wx > 0 && wy > 0 && square_check(x, y, cx-wx, cy-wy, cx+wx, cy+wy))
+         return INSIDE; /* between (inside) the boundary lines. */
+
+      return 0; /* inside the lines themselves. */
+   }
+
+   return OUTSIDE; /* outside the boundary lines. */
+}
+
+static int
+check_square_filled(const struct arg *arg, double x, double y)
+{
+   /* The filter extends +/-FILTER_WIDTH each side of each output point, so
+    * the check has to expand and contract the square by that amount; '0'
+    * means close enough to the edge of the square that the bicubic filter has
+    * to be run, OUTSIDE means alpha==0, INSIDE means alpha==1.
+    */
+   return square_check_line(arg, x, y, FILTER_WIDTH);
+}
+
+static int
+inside_square(const struct arg *arg, double x, double y)
+{
+   /* Return true if within the drawn lines, else false, no need to distinguish
+    * INSIDE vs OUTSIDE here:
+    */
+   return square_check_line(arg, x, y, arg->width/2) == 0;
+}
+
+static int
+check_square(const struct arg *arg, double x, double y)
+{
+   /* So for this function a result of 'INSIDE' means inside the actual lines.
+    */
+   double w = arg->width/2;
+
+   if (square_check_line(arg, x, y, w+FILTER_WIDTH) == 0)
+   {
+      /* Somewhere close to the boundary lines. If far enough inside one of
+       * them then we can return INSIDE:
+       */
+      w -= FILTER_WIDTH;
+
+      if (w > 0 && square_check_line(arg, x, y, w) == 0)
+         return INSIDE;
+
+      /* Point is somewhere in the filter region: */
+      return 0;
+   }
+
+   else /* Inside or outside the square by more than w+FILTER_WIDTH. */
+      return OUTSIDE;
+}
+
+/* "circle",
+ * { inside_circle_filled, check_circle_filled },
+ * { inside_circle, check_circle }
+ *
+ * The functions here are analoguous to the square ones; however, they check
+ * the corresponding ellipse as opposed to the rectangle.
+ */
+static int
+circle_check(double x, double y, double x1, double y1, double x2, double y2)
+{
+   if (square_check(x, y, x1, y1, x2, y2))
+   {
+      /* Inside the square, so maybe inside the circle too: */
+      const double cx = (x1 + x2)/2;
+      const double cy = (y1 + y2)/2;
+      const double dx = x1 - x2;
+      const double dy = y1 - y2;
+
+      x = (x - cx)/dx;
+      y = (y - cy)/dy;
+
+      /* It is outside if the distance from the center is more than half the
+       * diameter:
+       */
+      return x*x+y*y < .25;
+   }
+
+   return 0; /* outside */
+}
+
+static int
+inside_circle_filled(const struct arg *arg, double x, double y)
+{
+   return circle_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2);
+}
+
+static int
+circle_check_line(const struct arg *arg, double x, double y, double w)
+   /* Check for a point being inside the boundaries implied by the given arg
+    * and assuming a width 2*w each side of the boundaries.  This function has
+    * the same semantic as square_check_line but tests the circle.
+    */
+{
+   double cx = (arg->x1+arg->x2)/2;
+   double wx = fabs(arg->x1-arg->x2)/2;
+   double cy = (arg->y1+arg->y2)/2;
+   double wy = fabs(arg->y1-arg->y2)/2;
+
+   if (circle_check(x, y, cx-wx-w, cy-wy-w, cx+wx+w, cy+wy+w))
+   {
+      /* Inside, but maybe too far; check for the redundant case where
+       * the lines overlap:
+       */
+      wx -= w;
+      wy -= w;
+      if (wx > 0 && wy > 0 && circle_check(x, y, cx-wx, cy-wy, cx+wx, cy+wy))
+         return INSIDE; /* between (inside) the boundary lines. */
+
+      return 0; /* inside the lines themselves. */
+   }
+
+   return OUTSIDE; /* outside the boundary lines. */
+}
+
+static int
+check_circle_filled(const struct arg *arg, double x, double y)
+{
+   return circle_check_line(arg, x, y, FILTER_WIDTH);
+}
+
+static int
+inside_circle(const struct arg *arg, double x, double y)
+{
+   return circle_check_line(arg, x, y, arg->width/2) == 0;
+}
+
+static int
+check_circle(const struct arg *arg, double x, double y)
+{
+   /* Exactly as the 'square' code.  */
+   double w = arg->width/2;
+
+   if (circle_check_line(arg, x, y, w+FILTER_WIDTH) == 0)
+   {
+      w -= FILTER_WIDTH;
+
+      if (w > 0 && circle_check_line(arg, x, y, w) == 0)
+         return INSIDE;
+
+      /* Point is somewhere in the filter region: */
+      return 0;
+   }
+
+   else /* Inside or outside the square by more than w+FILTER_WIDTH. */
+      return OUTSIDE;
+}
+
+/* "line",
+ * { NULL, NULL },  There is no 'filled' line.
+ * { inside_line, check_line }
+ */
+static int
+line_check(double x, double y, double x1, double y1, double x2, double y2,
+   double w, double expand)
+{
+   /* Shift all the points to (arg->x1, arg->y1) */
+   double lx = x2 - x1;
+   double ly = y2 - y1;
+   double len2 = lx*lx + ly*ly;
+   double cross, dot;
+
+   x -= x1;
+   y -= y1;
+
+   /* The dot product is the distance down the line, the cross product is
+    * the distance away from the line:
+    *
+    *    distance = |cross| / sqrt(len2) 
+    */
+   cross = x * ly - y * lx;
+
+   /* If 'distance' is more than w the point is definitely outside the line:
+    *
+    *     distance >= w
+    *     |cross|  >= w * sqrt(len2)
+    *     cross^2  >= w^2 * len2:
+    */
+   if (cross*cross >= (w+expand)*(w+expand)*len2)
+      return 0; /* outside */
+
+   /* Now find the distance *along* the line; this comes from the dot product
+    * lx.x+ly.y. The actual distance (in pixels) is:
+    *
+    *   distance = dot / sqrt(len2)
+    */
+   dot = lx * x + ly * y;
+
+   /* The test for 'outside' is:
+    *
+    *    distance < 0 || distance > sqrt(len2)
+    *                 -> dot / sqrt(len2) > sqrt(len2)
+    *                 -> dot > len2
+    *
+    * But 'expand' is used for the filter width and needs to be handled too:
+    */
+   return dot > -expand && dot < len2+expand;
+}
+
+static int
+inside_line(const struct arg *arg, double x, double y)
+{
+   return line_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2, arg->width/2, 0);
+}
+
+static int
+check_line(const struct arg *arg, double x, double y)
+{
+   /* The end caps of the line must be checked too; it's not enough just to
+    * widen the line by FILTER_WIDTH; 'expand' exists for this purpose:
+    */
+   if (line_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2, arg->width/2,
+       FILTER_WIDTH))
+   {
+      /* Inside the line+filter; far enough inside that the filter isn't
+       * required?
+       */
+      if (arg->width > 2*FILTER_WIDTH &&
+          line_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2, arg->width/2,
+             -FILTER_WIDTH))
+         return INSIDE;
+
+      return 0;
+   }
+
+   return OUTSIDE;
+}
+
+static const struct
+{
+   const char    *name;
+   shape_fn_ptr   function[2/*fill,line*/][2];
+#  define         FN_INSIDE 0
+#  define         FN_CHECK 1
+} shape_defs[] =
+{
+   {  "square",
+      {  { inside_square_filled, check_square_filled },
+         { inside_square, check_square } }
+   },
+   {  "circle",
+      {  { inside_circle_filled, check_circle_filled },
+         { inside_circle, check_circle } }
+   },
+   {  "line",
+      {  { NULL, NULL },
+         { inside_line, check_line } }
+   }
+};
+
+#define shape_count ((sizeof shape_defs)/(sizeof shape_defs[0]))
+
+static shape_fn_ptr
+shape_of(const char *arg, double width, int f)
+{
+   unsigned int i;
+
+   for (i=0; i<shape_count; ++i) if (strcmp(shape_defs[i].name, arg) == 0)
+   {
+      shape_fn_ptr fn = shape_defs[i].function[width != 0][f];
+
+      if (fn != NULL)
+         return fn;
+
+      fprintf(stderr, "genpng: %s %s not supported\n",
+         width == 0 ? "filled" : "unfilled", arg);
+      exit(1);
+   }
+
+   fprintf(stderr, "genpng: %s: not a valid shape name\n", arg);
+   exit(1);
+}
+
+static void
+parse_arg(struct arg *arg, const char **argv/*7 arguments*/)
+{
+   /* shape ::= color width shape x1 y1 x2 y2 */
+   arg->color = color_of(argv[0]);
+   arg->width = width_of(argv[1]);
+   arg->inside_fn = shape_of(argv[2], arg->width, FN_INSIDE);
+   arg->check_fn = shape_of(argv[2], arg->width, FN_CHECK);
+   arg->x1 = coordinate_of(argv[3]);
+   arg->y1 = coordinate_of(argv[4]);
+   arg->x2 = coordinate_of(argv[5]);
+   arg->y2 = coordinate_of(argv[6]);
+}
+
+static png_uint_32
+read_wh(const char *name, const char *str)
+   /* read a PNG width or height */
+{
+   char *ep = NULL;
+   unsigned long ul = strtoul(str, &ep, 10);
+
+   if (ep != NULL && *ep == 0 && ul > 0 && ul <= 0x7fffffff)
+      return (png_uint_32)/*SAFE*/ul;
+
+   fprintf(stderr, "genpng: %s: invalid number %s\n", name, str);
+   exit(1);
+}
+
+static void
+pixel(png_uint_16p p, struct arg *args, int nargs, double x, double y)
+{
+   /* Fill in the pixel by checking each shape (args[nargs]) for effects on
+    * the corresponding sample:
+    */
+   double r=0, g=0, b=0, a=0;
+
+   while (--nargs >= 0 && a != 1)
+   {
+      /* NOTE: alpha_calc can return a value outside the range 0..1 with the
+       * bicubic filter.
+       */
+      const double alpha = alpha_calc(args+nargs, x, y) * (1-a);
+
+      r += alpha * args[nargs].color->red;
+      g += alpha * args[nargs].color->green;
+      b += alpha * args[nargs].color->blue;
+      a += alpha;
+   }
+
+   /* 'a' may be negative or greater than 1; if it is, negative clamp the
+    * pixel to 0 if >1 clamp r/g/b:
+    */
+   if (a > 0) 
+   {
+      if (a > 1)
+      {
+         if (r > 1) r = 1;
+         if (g > 1) g = 1;
+         if (b > 1) b = 1;
+         a = 1;
+      }
+
+      /* And fill in the pixel: */
+      p[0] = (png_uint_16)/*SAFE*/round(r * 65535);
+      p[1] = (png_uint_16)/*SAFE*/round(g * 65535);
+      p[2] = (png_uint_16)/*SAFE*/round(b * 65535);
+      p[3] = (png_uint_16)/*SAFE*/round(a * 65535);
+   }
+
+   else
+      p[3] = p[2] = p[1] = p[0] = 0;
+}
+
+int
+main(int argc, const char **argv)
+{
+   int convert_to_8bit = 0;
+
+   /* There is one option: --8bit: */
+   if (argc > 1 && strcmp(argv[1], "--8bit") == 0)
+      --argc, ++argv, convert_to_8bit = 1;
+
+   if (argc >= 3)
+   {
+      png_uint_16p buffer;
+      int nshapes;
+      png_image image;
+#     define max_shapes 256
+      struct arg arg_list[max_shapes];
+
+      /* The libpng Simplified API write code requires a fully initialized
+       * structure.
+       */
+      memset(&image, 0, sizeof image);
+      image.version = PNG_IMAGE_VERSION;
+      image.opaque = NULL;
+      image.width = read_wh("width", argv[1]);
+      image.height = read_wh("height", argv[2]);
+      image.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+      image.flags = 0;
+      image.colormap_entries = 0;
+
+      /* Check the remainder of the arguments */
+      for (nshapes=0; 3+7*(nshapes+1) <= argc && nshapes < max_shapes;
+           ++nshapes)
+         parse_arg(arg_list+nshapes, argv+3+7*nshapes);
+
+      if (3+7*nshapes != argc)
+      {
+         fprintf(stderr, "genpng: %s: too many arguments\n", argv[3+7*nshapes]);
+         return 1;
+      }
+
+      /* Create the buffer: */
+      buffer = malloc(PNG_IMAGE_SIZE(image));
+
+      if (buffer != NULL)
+      {
+         png_uint_32 y;
+
+         /* Write each row... */
+         for (y=0; y<image.height; ++y)
+         {
+            png_uint_32 x;
+
+            /* Each pixel in each row: */
+            for (x=0; x<image.width; ++x)
+               pixel(buffer + 4*(x + y*image.width), arg_list, nshapes, x, y);
+         }
+
+         /* Write the result (to stdout) */
+         if (png_image_write_to_stdio(&image, stdout, convert_to_8bit,
+             buffer, 0/*row_stride*/, NULL/*colormap*/))
+         {
+            free(buffer);
+            return 0; /* success */
+         }
+
+         else
+            fprintf(stderr, "genpng: write stdout: %s\n", image.message);
+
+         free(buffer);
+      }
+
+      else
+         fprintf(stderr, "genpng: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+   }
+
+   else
+   {
+      /* Wrong number of arguments */
+      fprintf(stderr, "genpng: usage: genpng [--8bit] width height {shape}\n"
+         " Generate a transparent PNG in RGBA (truecolor+alpha) format\n"
+         " containing the given shape or shapes.  Shapes are defined:\n"
+         "\n"
+         "  shape ::= color width shape x1 y1 x2 y2\n"
+         "  color ::= black|white|red|green|yellow|blue\n"
+         "  color ::= brown|purple|pink|orange|gray|cyan\n"
+         "  width ::= filled|<number>\n"
+         "  shape ::= circle|square|line\n"
+         "  x1,x2 ::= <number>\n"
+         "  y1,y2 ::= <number>\n"
+         "\n"
+         " Numbers are floating point numbers describing points relative to\n"
+         " the top left of the output PNG as pixel coordinates.  The 'width'\n"
+         " parameter is either the width of the line (in output pixels) used\n"
+         " to draw the shape or 'filled' to indicate that the shape should\n"
+         " be filled with the color.\n"
+         "\n"
+         " Colors are interpreted loosely to give access to the eight full\n"
+         " intensity RGB values:\n"
+         "\n"
+         "  black, red, green, blue, yellow, cyan, purple, white,\n"
+         "\n"
+         " Cyan is full intensity blue+green; RGB(0,1,1), plus the following\n"
+         " lower intensity values:\n"
+         "\n"
+         "  brown:  red+orange:  RGB(0.5, 0.125, 0) (dark red+orange)\n"
+         "  pink:   red+white:   RGB(1.0, 0.5,   0.5)\n"
+         "  orange: red+yellow:  RGB(1.0, 0.5,   0)\n"
+         "  gray:   black+white: RGB(0.5, 0.5,   0.5)\n"
+         "\n"
+         " The RGB values are selected to make detection of aliasing errors\n"
+         " easy. The names are selected to make the description of errors\n"
+         " easy.\n"
+         "\n"
+         " The PNG is written to stdout, if --8bit is given a 32bpp RGBA sRGB\n"
+         " file is produced, otherwise a 64bpp RGBA linear encoded file is\n"
+         " written.\n");
+   }
+
+   return 1;
+}
+#endif /* SIMPLIFIED_WRITE && STDIO */
--- a/contrib/tools/intgamma.sh
+++ b/contrib/tools/intgamma.sh
@@ -0,0 +1,110 @@
+#!/bin/sh
+#
+# intgamma.sh
+#
+# Last changed in libpng 1.6.0 [February 14, 2013]
+#
+# COPYRIGHT: Written by John Cunningham Bowler, 2013.
+# 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.
+#
+# Shell script to generate png.c 8-bit and 16-bit log tables (see the code in
+# png.c for details).
+#
+# This script uses the "bc" arbitrary precision calculator to calculate 32-bit
+# fixed point values of logarithms appropriate to finding the log of an 8-bit
+# (0..255) value and a similar table for the exponent calculation.
+#
+# "bc" must be on the path when the script is executed, and the math library
+# (-lm) must be available
+#
+# function to print out a list of numbers as integers; the function truncates
+# the integers which must be one-per-line
+function print(){
+   awk 'BEGIN{
+      str = ""
+   }
+   {
+      sub("\\.[0-9]*$", "")
+      if ($0 == "")
+         $0 = "0"
+
+      if (str == "")
+         t = "   " $0 "U"
+      else
+         t = str ", " $0 "U"
+
+      if (length(t) >= 80) {
+         print str ","
+         str = "   " $0 "U"
+      } else
+         str = t
+   }
+   END{
+      print str
+   }'
+}
+#
+# The logarithm table.
+cat <<END
+/* 8-bit log table: png_8bit_l2[128]
+ * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
+ * 255, so it's the base 2 logarithm of a normalized 8-bit floating point
+ * mantissa.  The numbers are 32-bit fractions.
+ */
+static const png_uint_32
+png_8bit_l2[128] =
+{
+END
+#
+bc -lqws <<END | print
+f=65536*65536/l(2)
+for (i=128;i<256;++i) { .5 - l(i/255)*f; }
+END
+echo '};'
+echo
+#
+# The exponent table.
+cat <<END
+/* The 'exp()' case must invert the above, taking a 20-bit fixed point
+ * logarithmic value and returning a 16 or 8-bit number as appropriate.  In
+ * each case only the low 16 bits are relevant - the fraction - since the
+ * integer bits (the top 4) simply determine a shift.
+ *
+ * The worst case is the 16-bit distinction between 65535 and 65534; this
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
+ * distinguish log2(65535/65534.5) - 10^-5 or 17 bits.  There is little chance
+ * of getting this accuracy in practice.
+ *
+ * To deal with this the following exp() function works out the exponent of the
+ * frational part of the logarithm by using an accurate 32-bit value from the
+ * top four fractional bits then multiplying in the remaining bits.
+ */
+static const png_uint_32
+png_32bit_exp[16] =
+{
+END
+#
+bc -lqws <<END | print
+f=l(2)/16
+for (i=0;i<16;++i) {
+   x = .5 + e(-i*f)*2^32;
+   if (x >= 2^32) x = 2^32-1;
+   x;
+}
+END
+echo '};'
+echo
+#
+# And the table of adjustment values.
+cat <<END
+/* Adjustment table; provided to explain the numbers in the code below. */
+#if 0
+END
+bc -lqws <<END | awk '{ printf "%5d %s\n", 12-NR, $0 }'
+for (i=11;i>=0;--i){
+   (1 - e(-(2^i)/65536*l(2))) * 2^(32-i)
+}
+END
+echo '#endif'
--- a/contrib/tools/makesRGB.c
+++ b/contrib/tools/makesRGB.c
@@ -0,0 +1,430 @@
+/* makesRGB.c -- build sRGB-to-linear and linear-to-sRGB conversion tables
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2013.
+ * 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.
+ *
+ * Make a table to convert 8-bit sRGB encoding values into the closest 16-bit
+ * linear value.
+ *
+ * Make two tables to take a linear value scaled to 255*65535 and return an
+ * approximation to the 8-bit sRGB encoded value.  Calculate the error in these
+ * tables and display it.
+ */
+#define _C99_SOURCE 1
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+
+/* pngpriv.h includes the definition of 'PNG_sRGB_FROM_LINEAR' which is required
+ * to verify the actual code.
+ */
+#include "../../pngpriv.h"
+
+#include "sRGB.h"
+
+/* The tables are declared 'const' in pngpriv.h, so this redefines the tables to
+ * be used.
+ */
+#define png_sRGB_table sRGB_table
+#define png_sRGB_base sRGB_base
+#define png_sRGB_delta sRGB_delta
+
+static png_uint_16 png_sRGB_table[256];
+static png_uint_16 png_sRGB_base[512];
+static png_byte png_sRGB_delta[512];
+
+static const unsigned int max_input = 255*65535;
+
+double
+fsRGB(double l)
+{
+   return sRGB_from_linear(l/max_input);
+}
+
+double
+sRGB(unsigned int i)
+{
+   return fsRGB(i);
+}
+
+double
+finvsRGB(unsigned int i)
+{
+   return 65535 * linear_from_sRGB(i/255.);
+}
+
+png_uint_16
+invsRGB(unsigned int i)
+{
+   unsigned int x = nearbyint(finvsRGB(i));
+
+   if (x > 65535)
+   {
+      fprintf(stderr, "invsRGB(%u) overflows to %u\n", i, x);
+      exit(1);
+   }
+
+   return (png_uint_16)x;
+}
+
+int
+main(int argc, char **argv)
+{
+   unsigned int i, i16, ibase;
+   double min_error = 0;
+   double max_error = 0;
+   double min_error16 = 0;
+   double max_error16 = 0;
+   double adjust;
+   double adjust_lo = 0.4, adjust_hi = 0.6, adjust_mid = 0.5;
+   unsigned int ec_lo = 0, ec_hi = 0, ec_mid = 0;
+   unsigned int error_count = 0;
+   unsigned int error_count16 = 0;
+   int test_only = 0;
+
+   if (argc > 1)
+      test_only = strcmp("--test", argv[1]) == 0;
+
+   /* Initialize the encoding table first. */
+   for (i=0; i<256; ++i)
+   {
+      png_sRGB_table[i] = invsRGB(i);
+   }
+
+   /* Now work out the decoding tables (this is where the error comes in because
+    * there are 512 set points and 512 straight lines between them.)
+    */
+   for (;;)
+   {
+      if (ec_lo == 0)
+         adjust = adjust_lo;
+
+      else if (ec_hi == 0)
+         adjust = adjust_hi;
+
+      else if (ec_mid == 0)
+         adjust = adjust_mid;
+
+      else if (ec_mid < ec_hi)
+         adjust = (adjust_mid + adjust_hi)/2;
+
+      else if (ec_mid < ec_lo)
+         adjust = (adjust_mid + adjust_lo)/2;
+
+      else
+      {
+         fprintf(stderr, "not reached: %u .. %u .. %u\n", ec_lo, ec_mid, ec_hi);
+         exit(1);
+      }
+
+      /* Calculate the table using the current 'adjust' */
+      for (i=0; i<=511; ++i)
+      {
+         double lo = 255 * sRGB(i << 15);
+         double hi = 255 * sRGB((i+1) << 15);
+         unsigned int calc;
+
+         calc = nearbyint((lo+adjust) * 256);
+         if (calc > 65535)
+         {
+            fprintf(stderr, "table[%d][0]: overflow %08x (%d)\n", i, calc,
+               calc);
+            exit(1);
+         }
+         png_sRGB_base[i] = calc;
+
+         calc = nearbyint((hi-lo) * 32);
+         if (calc > 255)
+         {
+            fprintf(stderr, "table[%d][1]: overflow %08x (%d)\n", i, calc,
+               calc);
+            exit(1);
+         }
+         png_sRGB_delta[i] = calc;
+      }
+
+      /* Check the 16-bit linear values alone: */
+      error_count16 = 0;
+      for (i16=0; i16 <= 65535; ++i16)
+      {
+         unsigned int i = 255*i16;
+         unsigned int iexact = nearbyint(255*sRGB(i));
+         unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+         if (icalc != iexact)
+            ++error_count16;
+      }
+
+      /* Now try changing the adjustment. */
+      if (ec_lo == 0)
+         ec_lo = error_count16;
+
+      else if (ec_hi == 0)
+         ec_hi = error_count16;
+
+      else if (ec_mid == 0)
+      {
+         ec_mid = error_count16;
+         printf("/* initial error counts: %u .. %u .. %u */\n", ec_lo, ec_mid,
+            ec_hi);
+      }
+
+      else if (error_count16 < ec_mid)
+      {
+         printf("/* adjust (mid ): %f: %u -> %u */\n", adjust, ec_mid,
+            error_count16);
+         ec_mid = error_count16;
+         adjust_mid = adjust;
+      }
+
+      else if (adjust < adjust_mid && error_count16 < ec_lo)
+      {
+         printf("/* adjust (low ): %f: %u -> %u */\n", adjust, ec_lo,
+            error_count16);
+         ec_lo = error_count16;
+         adjust_lo = adjust;
+      }
+
+      else if (adjust > adjust_mid && error_count16 < ec_hi)
+      {
+         printf("/* adjust (high): %f: %u -> %u */\n", adjust, ec_hi,
+            error_count16);
+         ec_hi = error_count16;
+         adjust_hi = adjust;
+      }
+
+      else
+      {
+         adjust = adjust_mid;
+         printf("/* adjust: %f: %u */\n", adjust, ec_mid);
+         break;
+      }
+   }
+
+   /* For each entry in the table try to adjust it to minimize the error count
+    * in that entry.  Each entry corresponds to 128 input values.
+    */
+   for (ibase=0; ibase<65536; ibase+=128)
+   {
+      png_uint_16 base = png_sRGB_base[ibase >> 7], trybase = base, ob=base;
+      png_byte delta = png_sRGB_delta[ibase >> 7], trydelta = delta, od=delta;
+      unsigned int ecbase = 0, eco;
+
+      for (;;)
+      {
+         png_sRGB_base[ibase >> 7] = trybase;
+         png_sRGB_delta[ibase >> 7] = trydelta;
+
+         /* Check the 16-bit linear values alone: */
+         error_count16 = 0;
+         for (i16=ibase; i16 < ibase+128; ++i16)
+         {
+            unsigned int i = 255*i16;
+            unsigned int iexact = nearbyint(255*sRGB(i));
+            unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+            if (icalc != iexact)
+               ++error_count16;
+         }
+
+         if (error_count16 == 0)
+            break;
+
+         if (ecbase == 0)
+         {
+            eco = ecbase = error_count16;
+            ++trybase; /* First test */
+         }
+
+         else if (error_count16 < ecbase)
+         {
+            if (trybase > base)
+            {
+               base = trybase;
+               ++trybase;
+            }
+            else if (trybase < base)
+            {
+               base = trybase;
+               --trybase;
+            }
+            else if (trydelta > delta)
+            {
+               delta = trydelta;
+               ++trydelta;
+            }
+            else if (trydelta < delta)
+            {
+               delta = trydelta;
+               --trydelta;
+            }
+            else
+            {
+               fprintf(stderr, "makesRGB: impossible\n");
+               exit(1);
+            }
+            ecbase = error_count16;
+         }
+
+         else
+         {
+            if (trybase > base)
+               trybase = base-1;
+            else if (trybase < base)
+            {
+               trybase = base;
+               ++trydelta;
+            }
+            else if (trydelta > delta)
+               trydelta = delta-1;
+            else if (trydelta < delta)
+               break; /* end of tests */
+         }
+      }
+
+      png_sRGB_base[ibase >> 7] = base;
+      png_sRGB_delta[ibase >> 7] = delta;
+      if (base != ob || delta != od)
+      {
+         printf("/* table[%u]={%u,%u} -> {%u,%u} %u -> %u errors */\n",
+            ibase>>7, ob, od, base, delta, eco, ecbase);
+      }
+      else if (0)
+         printf("/* table[%u]={%u,%u} %u errors */\n", ibase>>7, ob, od,
+            ecbase);
+   }
+
+   /* Only do the full (slow) test at the end: */
+   min_error = -.4999;
+   max_error = .4999;
+   error_count = 0;
+
+   for (i=0; i <= max_input; ++i)
+   {
+      unsigned int iexact = nearbyint(255*sRGB(i));
+      unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+      if (icalc != iexact)
+      {
+         double err = 255*sRGB(i) - icalc;
+
+         if (err > (max_error+.001) || err < (min_error-.001))
+         {
+            printf(
+               "/* 0x%08x: exact: %3d, got: %3d [tables: %08x, %08x] (%f) */\n",
+               i, iexact, icalc, png_sRGB_base[i>>15],
+               png_sRGB_delta[i>>15], err);
+         }
+
+         ++error_count;
+         if (err > max_error)
+            max_error = err;
+         else if (err < min_error)
+            min_error = err;
+      }
+   }
+
+   /* Re-check the 16-bit cases too, including the warning if there is an error
+    * bigger than 1.
+    */
+   error_count16 = 0;
+   max_error16 = 0;
+   min_error16 = 0;
+   for (i16=0; i16 <= 65535; ++i16)
+   {
+      unsigned int i = 255*i16;
+      unsigned int iexact = nearbyint(255*sRGB(i));
+      unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+      if (icalc != iexact)
+      {
+         double err = 255*sRGB(i) - icalc;
+
+         ++error_count16;
+         if (err > max_error16)
+            max_error16 = err;
+         else if (err < min_error16)
+            min_error16 = err;
+
+         if (abs(icalc - iexact) > 1)
+            printf(
+               "/* 0x%04x: exact: %3d, got: %3d [tables: %08x, %08x] (%f) */\n",
+               i16, iexact, icalc, png_sRGB_base[i>>15],
+               png_sRGB_delta[i>>15], err);
+      }
+   }
+
+   /* Check the round trip for each 8-bit sRGB value. */
+   for (i16=0; i16 <= 255; ++i16)
+   {
+      unsigned int i = 255 * png_sRGB_table[i16];
+      unsigned int iexact = nearbyint(255*sRGB(i));
+      unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+      if (i16 != iexact)
+      {
+         fprintf(stderr, "8-bit rounding error: %d -> %d\n", i16, iexact);
+         exit(1);
+      }
+
+      if (icalc != i16)
+      {
+         double finv = finvsRGB(i16);
+
+         printf("/* 8-bit roundtrip error: %d -> %f -> %d(%f) */\n",
+            i16, finv, icalc, fsRGB(255*finv));
+      }
+   }
+
+
+   printf("/* error: %g - %g, %u (%g%%) of readings inexact */\n",
+      min_error, max_error, error_count, (100.*error_count)/max_input);
+   printf("/* 16-bit error: %g - %g, %u (%g%%) of readings inexact */\n",
+      min_error16, max_error16, error_count16, (100.*error_count16)/65535);
+
+   if (!test_only)
+   {
+      printf("PNG_CONST png_uint_16 png_sRGB_table[256] =\n{\n   ");
+      for (i=0; i<255; )
+      {
+         do
+         {
+            printf("%d,", png_sRGB_table[i++]);
+         }
+         while ((i & 0x7) != 0 && i<255);
+         if (i<255) printf("\n   ");
+      }
+      printf("%d\n};\n\n", png_sRGB_table[i]);
+
+
+      printf("PNG_CONST png_uint_16 png_sRGB_base[512] =\n{\n   ");
+      for (i=0; i<511; )
+      {
+         do
+         {
+            printf("%d,", png_sRGB_base[i++]);
+         }
+         while ((i & 0x7) != 0 && i<511);
+         if (i<511) printf("\n   ");
+      }
+      printf("%d\n};\n\n", png_sRGB_base[i]);
+
+      printf("PNG_CONST png_byte png_sRGB_delta[512] =\n{\n   ");
+      for (i=0; i<511; )
+      {
+         do
+         {
+            printf("%d,", png_sRGB_delta[i++]);
+         }
+         while ((i & 0xf) != 0 && i<511);
+         if (i<511) printf("\n   ");
+      }
+      printf("%d\n};\n\n", png_sRGB_delta[i]);
+   }
+
+   return 0;
+}
--- a/contrib/tools/png-fix-itxt.c
+++ b/contrib/tools/png-fix-itxt.c
@@ -0,0 +1,164 @@
+
+/* png-fix-itxt version 1.0.0
+ *
+ * Copyright 2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.18 [July 23, 2015]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Usage:            
+ *
+ *     png-fix-itxt.exe < bad.png > good.png
+ *
+ * Fixes a PNG file written with libpng-1.6.0 or 1.6.1 that has one or more
+ * uncompressed iTXt chunks.  Assumes that the actual length is greater
+ * than or equal to the value in the length byte, and that the CRC is
+ * correct for the actual length.  This program hunts for the CRC and
+ * adjusts the length byte accordingly.  It is not an error to process a
+ * PNG file that has no iTXt chunks or one that has valid iTXt chunks;
+ * such files will simply be copied.
+ *
+ * Requires zlib (for crc32 and Z_NULL); build with
+ *
+ *     gcc -O -o png-fix-itxt png-fix-itxt.c -lz
+ *
+ * If you need to handle iTXt chunks larger than 500000 kbytes you must
+ * rebuild png-fix-itxt with a larger values of MAX_LENGTH (or a smaller value
+ * if you know you will never encounter such huge iTXt chunks).
+ */
+
+#include <stdio.h>
+#include <zlib.h>
+
+#define MAX_LENGTH 500000
+
+/* Read one character (inchar), also return octet (c), break if EOF */
+#define GETBREAK inchar=getchar(); \
+                 c=(inchar & 0xffU);\
+                 if (inchar != c) break
+int
+main(void)
+{
+   unsigned int i;
+   unsigned char buf[MAX_LENGTH];
+   unsigned long crc;
+   unsigned char c;
+   int inchar;
+
+/* Skip 8-byte signature */
+   for (i=8; i; i--)
+   {
+      GETBREAK;
+      putchar(c);
+   }
+
+if (inchar == c) /* !EOF */
+for (;;)
+ {
+   /* Read the length */
+   unsigned long length; /* must be 32 bits! */
+   GETBREAK; buf[0] = c; length  = c; length <<= 8;
+   GETBREAK; buf[1] = c; length += c; length <<= 8;
+   GETBREAK; buf[2] = c; length += c; length <<= 8;
+   GETBREAK; buf[3] = c; length += c;
+
+   /* Read the chunkname */
+   GETBREAK; buf[4] = c;
+   GETBREAK; buf[5] = c;
+   GETBREAK; buf[6] = c;
+   GETBREAK; buf[7] = c;
+
+
+   /* The iTXt chunk type expressed as integers is (105, 84, 88, 116) */
+   if (buf[4] == 105 && buf[5] == 84 && buf[6] == 88 && buf[7] == 116)
+   {
+      if (length >= MAX_LENGTH-12)
+         break;  /* To do: handle this more gracefully */
+
+      /* Initialize the CRC */
+      crc = crc32(0, Z_NULL, 0);
+
+      /* Copy the data bytes */
+      for (i=8; i < length + 12; i++)
+      {
+         GETBREAK; buf[i] = c;
+      }
+
+      if (inchar != c) /* EOF */
+         break;
+
+      /* Calculate the CRC */
+      crc = crc32(crc, buf+4, (uInt)length+4);
+
+      for (;;)
+      {
+        /* Check the CRC */
+        if (((crc >> 24) & 0xffU) == buf[length+8] &&
+            ((crc >> 16) & 0xffU) == buf[length+9] &&
+            ((crc >>  8) & 0xffU) == buf[length+10] &&
+            ((crc      ) & 0xffU) == buf[length+11])
+           break;
+
+        length++;
+
+        if (length >= MAX_LENGTH-12)
+           break;
+
+        GETBREAK;
+        buf[length+11] = c;
+
+        /* Update the CRC */
+        crc = crc32(crc, buf+7+length, 1);
+      }
+
+      if (inchar != c) /* EOF */
+         break;
+
+      /* Update length bytes */
+      buf[0] = (unsigned char)((length >> 24) & 0xffU);
+      buf[1] = (unsigned char)((length >> 16) & 0xffU);
+      buf[2] = (unsigned char)((length >>  8) & 0xffU);
+      buf[3] = (unsigned char)((length      ) & 0xffU);
+
+      /* Write the fixed iTXt chunk (length, name, data, crc) */
+      for (i=0; i<length+12; i++)
+         putchar(buf[i]);
+   }
+
+   else
+   {
+      if (inchar != c) /* EOF */
+         break;
+
+      /* Copy bytes that were already read (length and chunk name) */
+      for (i=0; i<8; i++)
+         putchar(buf[i]);
+
+      /* Copy data bytes and CRC */
+      for (i=8; i< length+12; i++)
+      {
+         GETBREAK;
+         putchar(c);
+      }
+
+      if (inchar != c) /* EOF */
+      {
+         break;
+      }
+
+   /* The IEND chunk type expressed as integers is (73, 69, 78, 68) */
+      if (buf[4] == 73 && buf[5] == 69 && buf[6] == 78 && buf[7] == 68)
+         break;
+   }
+
+   if (inchar != c) /* EOF */
+      break;
+
+   if (buf[4] == 73 && buf[5] == 69 && buf[6] == 78 && buf[7] == 68)
+     break;
+ }
+
+ return 0;
+}
--- a/contrib/tools/pngfix.c
+++ b/contrib/tools/pngfix.c
--- a/contrib/tools/sRGB.h
+++ b/contrib/tools/sRGB.h
@@ -0,0 +1,48 @@
+/*-
+ * sRGB.h
+ *
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2013.
+ * 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.
+ *
+ * Utility file; not actually a header, this contains definitions of sRGB
+ * calculation functions for inclusion in those test programs that need them.
+ *
+ * All routines take and return a floating point value in the range
+ * 0 to 1.0, doing a calculation according to the sRGB specification
+ * (in fact the source of the numbers is the wikipedia article at
+ * http://en.wikipedia.org/wiki/SRGB).
+ */
+static double
+sRGB_from_linear(double l)
+{
+   if (l <= 0.0031308)
+      l *= 12.92;
+
+   else
+      l = 1.055 * pow(l, 1/2.4) - 0.055;
+
+   return l;
+}
+
+static double
+linear_from_sRGB(double s)
+{
+   if (s <= 0.04045)
+      return s / 12.92;
+
+   else
+      return pow((s+0.055)/1.055, 2.4);
+}
+
+static double
+YfromRGB(double r, double g, double b)
+{
+   /* Use the sRGB (rounded) coefficients for Rlinear, Glinear, Blinear to get
+    * the CIE Y value (also linear).
+    */
+   return 0.2126 * r + 0.7152 * g + 0.0722 * b;
+}
--- a/contrib/visupng/PngFile.c
+++ b/contrib/visupng/PngFile.c
@@ -13,6 +13,7 @@
 #include <commdlg.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <zlib.h>

 #include "png.h"
 #include "pngfile.h"
@@ -135,7 +136,7 @@ BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,

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

-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), NULL,
      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
    if (!png_ptr)
    {
@@ -312,7 +313,7 @@ BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,

    /* prepare the standard PNG structures */

-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
+    png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), NULL,
      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
    if (!png_ptr)
    {
--- a/contrib/visupng/PngFile.h
+++ b/contrib/visupng/PngFile.h
@@ -17,7 +17,7 @@ void PngFileInitialize (HWND hwnd) ;
 BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;
 BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;

-BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData, 
+BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor);
 BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
                   int iWidth, int iHeight, png_color BkgColor);
--- a/contrib/visupng/VisualPng.c
+++ b/contrib/visupng/VisualPng.c
@@ -27,6 +27,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <windows.h>
+#include <zlib.h>

 /* application includes */

--- a/contrib/visupng/cexcept.h
+++ b/contrib/visupng/cexcept.h
@@ -1,11 +1,12 @@
 /*===
-cexcept.h 2.0.1 (2008-Jul-19-Sat)
+cexcept.h 2.0.1 (2008-Jul-19-Sat, modified 2015-Jun-03-Mon)
 http://www.nicemice.net/cexcept/
 Adam M. Costello
 http://www.nicemice.net/amc/

 An interface for exception-handling in ANSI C (C89 and subsequent ISO
-standards), developed jointly with Cosmin Truta.
+standards), developed jointly with Cosmin Truta.  Revised by John Bowler,
+June 2015, to declare exception_env and exception_prev "volatile".

    Copyright (c) 2000-2008 Adam M. Costello and Cosmin Truta.
    This software may be modified only if its author and version
@@ -210,7 +211,7 @@ struct exception_context { \

 #define Try \
  { \
-    jmp_buf *exception__prev, exception__env; \
+    jmp_buf * volatile exception__prev, exception__env; \
    exception__prev = the_exception_context->penv; \
    the_exception_context->penv = &exception__env; \
    if (setjmp(exception__env) == 0) { \
--- a/688
+++ b/688
@@ -1,688 +0,0 @@
-#! /bin/sh
-# depcomp - compile a program generating dependencies as side-effects
-
-scriptversion=2011-12-04.11; # UTC
-
-# Copyright (C) 1999, 2000, 2003, 2004, 2005, 2006, 2007, 2009, 2010,
-# 2011 Free Software Foundation, Inc.
-
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# As a special exception to the GNU General Public License, if you
-# distribute this file as part of a program that contains a
-# configuration script generated by Autoconf, you may include it under
-# the same distribution terms that you use for the rest of that program.
-
-# Originally written by Alexandre Oliva <oliva@dcc.unicamp.br>.
-
-case $1 in
-  '')
-     echo "$0: No command.  Try \`$0 --help' for more information." 1>&2
-     exit 1;
-     ;;
-  -h | --h*)
-    cat <<\EOF
-Usage: depcomp [--help] [--version] PROGRAM [ARGS]
-
-Run PROGRAMS ARGS to compile a file, generating dependencies
-as side-effects.
-
-Environment variables:
-  depmode     Dependency tracking mode.
-  source      Source file read by `PROGRAMS ARGS'.
-  object      Object file output by `PROGRAMS ARGS'.
-  DEPDIR      directory where to store dependencies.
-  depfile     Dependency file to output.
-  tmpdepfile  Temporary file to use when outputting dependencies.
-  libtool     Whether libtool is used (yes/no).
-
-Report bugs to <bug-automake@gnu.org>.
-EOF
-    exit $?
-    ;;
-  -v | --v*)
-    echo "depcomp $scriptversion"
-    exit $?
-    ;;
-esac
-
-if test -z "$depmode" || test -z "$source" || test -z "$object"; then
-  echo "depcomp: Variables source, object and depmode must be set" 1>&2
-  exit 1
-fi
-
-# Dependencies for sub/bar.o or sub/bar.obj go into sub/.deps/bar.Po.
-depfile=${depfile-`echo "$object" |
-  sed 's|[^\\/]*$|'${DEPDIR-.deps}'/&|;s|\.\([^.]*\)$|.P\1|;s|Pobj$|Po|'`}
-tmpdepfile=${tmpdepfile-`echo "$depfile" | sed 's/\.\([^.]*\)$/.T\1/'`}
-
-rm -f "$tmpdepfile"
-
-# Some modes work just like other modes, but use different flags.  We
-# parameterize here, but still list the modes in the big case below,
-# to make depend.m4 easier to write.  Note that we *cannot* use a case
-# here, because this file can only contain one case statement.
-if test "$depmode" = hp; then
-  # HP compiler uses -M and no extra arg.
-  gccflag=-M
-  depmode=gcc
-fi
-
-if test "$depmode" = dashXmstdout; then
-   # This is just like dashmstdout with a different argument.
-   dashmflag=-xM
-   depmode=dashmstdout
-fi
-
-cygpath_u="cygpath -u -f -"
-if test "$depmode" = msvcmsys; then
-   # This is just like msvisualcpp but w/o cygpath translation.
-   # Just convert the backslash-escaped backslashes to single forward
-   # slashes to satisfy depend.m4
-   cygpath_u='sed s,\\\\,/,g'
-   depmode=msvisualcpp
-fi
-
-if test "$depmode" = msvc7msys; then
-   # This is just like msvc7 but w/o cygpath translation.
-   # Just convert the backslash-escaped backslashes to single forward
-   # slashes to satisfy depend.m4
-   cygpath_u='sed s,\\\\,/,g'
-   depmode=msvc7
-fi
-
-case "$depmode" in
-gcc3)
-## gcc 3 implements dependency tracking that does exactly what
-## we want.  Yay!  Note: for some reason libtool 1.4 doesn't like
-## it if -MD -MP comes after the -MF stuff.  Hmm.
-## Unfortunately, FreeBSD c89 acceptance of flags depends upon
-## the command line argument order; so add the flags where they
-## appear in depend2.am.  Note that the slowdown incurred here
-## affects only configure: in makefiles, %FASTDEP% shortcuts this.
-  for arg
-  do
-    case $arg in
-    -c) set fnord "$@" -MT "$object" -MD -MP -MF "$tmpdepfile" "$arg" ;;
-    *)  set fnord "$@" "$arg" ;;
-    esac
-    shift # fnord
-    shift # $arg
-  done
-  "$@"
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  mv "$tmpdepfile" "$depfile"
-  ;;
-
-gcc)
-## There are various ways to get dependency output from gcc.  Here's
-## why we pick this rather obscure method:
-## - Don't want to use -MD because we'd like the dependencies to end
-##   up in a subdir.  Having to rename by hand is ugly.
-##   (We might end up doing this anyway to support other compilers.)
-## - The DEPENDENCIES_OUTPUT environment variable makes gcc act like
-##   -MM, not -M (despite what the docs say).
-## - Using -M directly means running the compiler twice (even worse
-##   than renaming).
-  if test -z "$gccflag"; then
-    gccflag=-MD,
-  fi
-  "$@" -Wp,"$gccflag$tmpdepfile"
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  rm -f "$depfile"
-  echo "$object : \\" > "$depfile"
-  alpha=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
-## The second -e expression handles DOS-style file names with drive letters.
-  sed -e 's/^[^:]*: / /' \
-      -e 's/^['$alpha']:\/[^:]*: / /' < "$tmpdepfile" >> "$depfile"
-## This next piece of magic avoids the `deleted header file' problem.
-## The problem is that when a header file which appears in a .P file
-## is deleted, the dependency causes make to die (because there is
-## typically no way to rebuild the header).  We avoid this by adding
-## dummy dependencies for each header file.  Too bad gcc doesn't do
-## this for us directly.
-  tr ' ' '
-' < "$tmpdepfile" |
-## Some versions of gcc put a space before the `:'.  On the theory
-## that the space means something, we add a space to the output as
-## well.  hp depmode also adds that space, but also prefixes the VPATH
-## to the object.  Take care to not repeat it in the output.
-## Some versions of the HPUX 10.20 sed can't process this invocation
-## correctly.  Breaking it into two sed invocations is a workaround.
-    sed -e 's/^\\$//' -e '/^$/d' -e "s|.*$object$||" -e '/:$/d' \
-      | sed -e 's/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-hp)
-  # This case exists only to let depend.m4 do its work.  It works by
-  # looking at the text of this script.  This case will never be run,
-  # since it is checked for above.
-  exit 1
-  ;;
-
-sgi)
-  if test "$libtool" = yes; then
-    "$@" "-Wp,-MDupdate,$tmpdepfile"
-  else
-    "$@" -MDupdate "$tmpdepfile"
-  fi
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  rm -f "$depfile"
-
-  if test -f "$tmpdepfile"; then  # yes, the sourcefile depend on other files
-    echo "$object : \\" > "$depfile"
-
-    # Clip off the initial element (the dependent).  Don't try to be
-    # clever and replace this with sed code, as IRIX sed won't handle
-    # lines with more than a fixed number of characters (4096 in
-    # IRIX 6.2 sed, 8192 in IRIX 6.5).  We also remove comment lines;
-    # the IRIX cc adds comments like `#:fec' to the end of the
-    # dependency line.
-    tr ' ' '
-' < "$tmpdepfile" \
-    | sed -e 's/^.*\.o://' -e 's/#.*$//' -e '/^$/ d' | \
-    tr '
-' ' ' >> "$depfile"
-    echo >> "$depfile"
-
-    # The second pass generates a dummy entry for each header file.
-    tr ' ' '
-' < "$tmpdepfile" \
-   | sed -e 's/^.*\.o://' -e 's/#.*$//' -e '/^$/ d' -e 's/$/:/' \
-   >> "$depfile"
-  else
-    # The sourcefile does not contain any dependencies, so just
-    # store a dummy comment line, to avoid errors with the Makefile
-    # "include basename.Plo" scheme.
-    echo "#dummy" > "$depfile"
-  fi
-  rm -f "$tmpdepfile"
-  ;;
-
-aix)
-  # The C for AIX Compiler uses -M and outputs the dependencies
-  # in a .u file.  In older versions, this file always lives in the
-  # current directory.  Also, the AIX compiler puts `$object:' at the
-  # start of each line; $object doesn't have directory information.
-  # Version 6 uses the directory in both cases.
-  dir=`echo "$object" | sed -e 's|/[^/]*$|/|'`
-  test "x$dir" = "x$object" && dir=
-  base=`echo "$object" | sed -e 's|^.*/||' -e 's/\.o$//' -e 's/\.lo$//'`
-  if test "$libtool" = yes; then
-    tmpdepfile1=$dir$base.u
-    tmpdepfile2=$base.u
-    tmpdepfile3=$dir.libs/$base.u
-    "$@" -Wc,-M
-  else
-    tmpdepfile1=$dir$base.u
-    tmpdepfile2=$dir$base.u
-    tmpdepfile3=$dir$base.u
-    "$@" -M
-  fi
-  stat=$?
-
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
-    exit $stat
-  fi
-
-  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
-  do
-    test -f "$tmpdepfile" && break
-  done
-  if test -f "$tmpdepfile"; then
-    # Each line is of the form `foo.o: dependent.h'.
-    # Do two passes, one to just change these to
-    # `$object: dependent.h' and one to simply `dependent.h:'.
-    sed -e "s,^.*\.[a-z]*:,$object:," < "$tmpdepfile" > "$depfile"
-    # That's a tab and a space in the [].
-    sed -e 's,^.*\.[a-z]*:[	 ]*,,' -e 's,$,:,' < "$tmpdepfile" >> "$depfile"
-  else
-    # The sourcefile does not contain any dependencies, so just
-    # store a dummy comment line, to avoid errors with the Makefile
-    # "include basename.Plo" scheme.
-    echo "#dummy" > "$depfile"
-  fi
-  rm -f "$tmpdepfile"
-  ;;
-
-icc)
-  # Intel's C compiler understands `-MD -MF file'.  However on
-  #    icc -MD -MF foo.d -c -o sub/foo.o sub/foo.c
-  # ICC 7.0 will fill foo.d with something like
-  #    foo.o: sub/foo.c
-  #    foo.o: sub/foo.h
-  # which is wrong.  We want:
-  #    sub/foo.o: sub/foo.c
-  #    sub/foo.o: sub/foo.h
-  #    sub/foo.c:
-  #    sub/foo.h:
-  # ICC 7.1 will output
-  #    foo.o: sub/foo.c sub/foo.h
-  # and will wrap long lines using \ :
-  #    foo.o: sub/foo.c ... \
-  #     sub/foo.h ... \
-  #     ...
-
-  "$@" -MD -MF "$tmpdepfile"
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  rm -f "$depfile"
-  # Each line is of the form `foo.o: dependent.h',
-  # or `foo.o: dep1.h dep2.h \', or ` dep3.h dep4.h \'.
-  # Do two passes, one to just change these to
-  # `$object: dependent.h' and one to simply `dependent.h:'.
-  sed "s,^[^:]*:,$object :," < "$tmpdepfile" > "$depfile"
-  # Some versions of the HPUX 10.20 sed can't process this invocation
-  # correctly.  Breaking it into two sed invocations is a workaround.
-  sed 's,^[^:]*: \(.*\)$,\1,;s/^\\$//;/^$/d;/:$/d' < "$tmpdepfile" |
-    sed -e 's/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-hp2)
-  # The "hp" stanza above does not work with aCC (C++) and HP's ia64
-  # compilers, which have integrated preprocessors.  The correct option
-  # to use with these is +Maked; it writes dependencies to a file named
-  # 'foo.d', which lands next to the object file, wherever that
-  # happens to be.
-  # Much of this is similar to the tru64 case; see comments there.
-  dir=`echo "$object" | sed -e 's|/[^/]*$|/|'`
-  test "x$dir" = "x$object" && dir=
-  base=`echo "$object" | sed -e 's|^.*/||' -e 's/\.o$//' -e 's/\.lo$//'`
-  if test "$libtool" = yes; then
-    tmpdepfile1=$dir$base.d
-    tmpdepfile2=$dir.libs/$base.d
-    "$@" -Wc,+Maked
-  else
-    tmpdepfile1=$dir$base.d
-    tmpdepfile2=$dir$base.d
-    "$@" +Maked
-  fi
-  stat=$?
-  if test $stat -eq 0; then :
-  else
-     rm -f "$tmpdepfile1" "$tmpdepfile2"
-     exit $stat
-  fi
-
-  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2"
-  do
-    test -f "$tmpdepfile" && break
-  done
-  if test -f "$tmpdepfile"; then
-    sed -e "s,^.*\.[a-z]*:,$object:," "$tmpdepfile" > "$depfile"
-    # Add `dependent.h:' lines.
-    sed -ne '2,${
-	       s/^ *//
-	       s/ \\*$//
-	       s/$/:/
-	       p
-	     }' "$tmpdepfile" >> "$depfile"
-  else
-    echo "#dummy" > "$depfile"
-  fi
-  rm -f "$tmpdepfile" "$tmpdepfile2"
-  ;;
-
-tru64)
-   # The Tru64 compiler uses -MD to generate dependencies as a side
-   # effect.  `cc -MD -o foo.o ...' puts the dependencies into `foo.o.d'.
-   # At least on Alpha/Redhat 6.1, Compaq CCC V6.2-504 seems to put
-   # dependencies in `foo.d' instead, so we check for that too.
-   # Subdirectories are respected.
-   dir=`echo "$object" | sed -e 's|/[^/]*$|/|'`
-   test "x$dir" = "x$object" && dir=
-   base=`echo "$object" | sed -e 's|^.*/||' -e 's/\.o$//' -e 's/\.lo$//'`
-
-   if test "$libtool" = yes; then
-      # With Tru64 cc, shared objects can also be used to make a
-      # static library.  This mechanism is used in libtool 1.4 series to
-      # handle both shared and static libraries in a single compilation.
-      # With libtool 1.4, dependencies were output in $dir.libs/$base.lo.d.
-      #
-      # With libtool 1.5 this exception was removed, and libtool now
-      # generates 2 separate objects for the 2 libraries.  These two
-      # compilations output dependencies in $dir.libs/$base.o.d and
-      # in $dir$base.o.d.  We have to check for both files, because
-      # one of the two compilations can be disabled.  We should prefer
-      # $dir$base.o.d over $dir.libs/$base.o.d because the latter is
-      # automatically cleaned when .libs/ is deleted, while ignoring
-      # the former would cause a distcleancheck panic.
-      tmpdepfile1=$dir.libs/$base.lo.d   # libtool 1.4
-      tmpdepfile2=$dir$base.o.d          # libtool 1.5
-      tmpdepfile3=$dir.libs/$base.o.d    # libtool 1.5
-      tmpdepfile4=$dir.libs/$base.d      # Compaq CCC V6.2-504
-      "$@" -Wc,-MD
-   else
-      tmpdepfile1=$dir$base.o.d
-      tmpdepfile2=$dir$base.d
-      tmpdepfile3=$dir$base.d
-      tmpdepfile4=$dir$base.d
-      "$@" -MD
-   fi
-
-   stat=$?
-   if test $stat -eq 0; then :
-   else
-      rm -f "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3" "$tmpdepfile4"
-      exit $stat
-   fi
-
-   for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3" "$tmpdepfile4"
-   do
-     test -f "$tmpdepfile" && break
-   done
-   if test -f "$tmpdepfile"; then
-      sed -e "s,^.*\.[a-z]*:,$object:," < "$tmpdepfile" > "$depfile"
-      # That's a tab and a space in the [].
-      sed -e 's,^.*\.[a-z]*:[	 ]*,,' -e 's,$,:,' < "$tmpdepfile" >> "$depfile"
-   else
-      echo "#dummy" > "$depfile"
-   fi
-   rm -f "$tmpdepfile"
-   ;;
-
-msvc7)
-  if test "$libtool" = yes; then
-    showIncludes=-Wc,-showIncludes
-  else
-    showIncludes=-showIncludes
-  fi
-  "$@" $showIncludes > "$tmpdepfile"
-  stat=$?
-  grep -v '^Note: including file: ' "$tmpdepfile"
-  if test "$stat" = 0; then :
-  else
-    rm -f "$tmpdepfile"
-    exit $stat
-  fi
-  rm -f "$depfile"
-  echo "$object : \\" > "$depfile"
-  # The first sed program below extracts the file names and escapes
-  # backslashes for cygpath.  The second sed program outputs the file
-  # name when reading, but also accumulates all include files in the
-  # hold buffer in order to output them again at the end.  This only
-  # works with sed implementations that can handle large buffers.
-  sed < "$tmpdepfile" -n '
-/^Note: including file:  *\(.*\)/ {
-  s//\1/
-  s/\\/\\\\/g
-  p
-}' | $cygpath_u | sort -u | sed -n '
-s/ /\\ /g
-s/\(.*\)/	\1 \\/p
-s/.\(.*\) \\/\1:/
-H
-$ {
-  s/.*/	/
-  G
-  p
-}' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-msvc7msys)
-  # This case exists only to let depend.m4 do its work.  It works by
-  # looking at the text of this script.  This case will never be run,
-  # since it is checked for above.
-  exit 1
-  ;;
-
-#nosideeffect)
-  # This comment above is used by automake to tell side-effect
-  # dependency tracking mechanisms from slower ones.
-
-dashmstdout)
-  # Important note: in order to support this mode, a compiler *must*
-  # always write the preprocessed file to stdout, regardless of -o.
-  "$@" || exit $?
-
-  # Remove the call to Libtool.
-  if test "$libtool" = yes; then
-    while test "X$1" != 'X--mode=compile'; do
-      shift
-    done
-    shift
-  fi
-
-  # Remove `-o $object'.
-  IFS=" "
-  for arg
-  do
-    case $arg in
-    -o)
-      shift
-      ;;
-    $object)
-      shift
-      ;;
-    *)
-      set fnord "$@" "$arg"
-      shift # fnord
-      shift # $arg
-      ;;
-    esac
-  done
-
-  test -z "$dashmflag" && dashmflag=-M
-  # Require at least two characters before searching for `:'
-  # in the target name.  This is to cope with DOS-style filenames:
-  # a dependency such as `c:/foo/bar' could be seen as target `c' otherwise.
-  "$@" $dashmflag |
-    sed 's:^[  ]*[^: ][^:][^:]*\:[    ]*:'"$object"'\: :' > "$tmpdepfile"
-  rm -f "$depfile"
-  cat < "$tmpdepfile" > "$depfile"
-  tr ' ' '
-' < "$tmpdepfile" | \
-## Some versions of the HPUX 10.20 sed can't process this invocation
-## correctly.  Breaking it into two sed invocations is a workaround.
-    sed -e 's/^\\$//' -e '/^$/d' -e '/:$/d' | sed -e 's/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-dashXmstdout)
-  # This case only exists to satisfy depend.m4.  It is never actually
-  # run, as this mode is specially recognized in the preamble.
-  exit 1
-  ;;
-
-makedepend)
-  "$@" || exit $?
-  # Remove any Libtool call
-  if test "$libtool" = yes; then
-    while test "X$1" != 'X--mode=compile'; do
-      shift
-    done
-    shift
-  fi
-  # X makedepend
-  shift
-  cleared=no eat=no
-  for arg
-  do
-    case $cleared in
-    no)
-      set ""; shift
-      cleared=yes ;;
-    esac
-    if test $eat = yes; then
-      eat=no
-      continue
-    fi
-    case "$arg" in
-    -D*|-I*)
-      set fnord "$@" "$arg"; shift ;;
-    # Strip any option that makedepend may not understand.  Remove
-    # the object too, otherwise makedepend will parse it as a source file.
-    -arch)
-      eat=yes ;;
-    -*|$object)
-      ;;
-    *)
-      set fnord "$@" "$arg"; shift ;;
-    esac
-  done
-  obj_suffix=`echo "$object" | sed 's/^.*\././'`
-  touch "$tmpdepfile"
-  ${MAKEDEPEND-makedepend} -o"$obj_suffix" -f"$tmpdepfile" "$@"
-  rm -f "$depfile"
-  # makedepend may prepend the VPATH from the source file name to the object.
-  # No need to regex-escape $object, excess matching of '.' is harmless.
-  sed "s|^.*\($object *:\)|\1|" "$tmpdepfile" > "$depfile"
-  sed '1,2d' "$tmpdepfile" | tr ' ' '
-' | \
-## Some versions of the HPUX 10.20 sed can't process this invocation
-## correctly.  Breaking it into two sed invocations is a workaround.
-    sed -e 's/^\\$//' -e '/^$/d' -e '/:$/d' | sed -e 's/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile" "$tmpdepfile".bak
-  ;;
-
-cpp)
-  # Important note: in order to support this mode, a compiler *must*
-  # always write the preprocessed file to stdout.
-  "$@" || exit $?
-
-  # Remove the call to Libtool.
-  if test "$libtool" = yes; then
-    while test "X$1" != 'X--mode=compile'; do
-      shift
-    done
-    shift
-  fi
-
-  # Remove `-o $object'.
-  IFS=" "
-  for arg
-  do
-    case $arg in
-    -o)
-      shift
-      ;;
-    $object)
-      shift
-      ;;
-    *)
-      set fnord "$@" "$arg"
-      shift # fnord
-      shift # $arg
-      ;;
-    esac
-  done
-
-  "$@" -E |
-    sed -n -e '/^# [0-9][0-9]* "\([^"]*\)".*/ s:: \1 \\:p' \
-       -e '/^#line [0-9][0-9]* "\([^"]*\)".*/ s:: \1 \\:p' |
-    sed '$ s: \\$::' > "$tmpdepfile"
-  rm -f "$depfile"
-  echo "$object : \\" > "$depfile"
-  cat < "$tmpdepfile" >> "$depfile"
-  sed < "$tmpdepfile" '/^$/d;s/^ //;s/ \\$//;s/$/ :/' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-msvisualcpp)
-  # Important note: in order to support this mode, a compiler *must*
-  # always write the preprocessed file to stdout.
-  "$@" || exit $?
-
-  # Remove the call to Libtool.
-  if test "$libtool" = yes; then
-    while test "X$1" != 'X--mode=compile'; do
-      shift
-    done
-    shift
-  fi
-
-  IFS=" "
-  for arg
-  do
-    case "$arg" in
-    -o)
-      shift
-      ;;
-    $object)
-      shift
-      ;;
-    "-Gm"|"/Gm"|"-Gi"|"/Gi"|"-ZI"|"/ZI")
-	set fnord "$@"
-	shift
-	shift
-	;;
-    *)
-	set fnord "$@" "$arg"
-	shift
-	shift
-	;;
-    esac
-  done
-  "$@" -E 2>/dev/null |
-  sed -n '/^#line [0-9][0-9]* "\([^"]*\)"/ s::\1:p' | $cygpath_u | sort -u > "$tmpdepfile"
-  rm -f "$depfile"
-  echo "$object : \\" > "$depfile"
-  sed < "$tmpdepfile" -n -e 's% %\\ %g' -e '/^\(.*\)$/ s::	\1 \\:p' >> "$depfile"
-  echo "	" >> "$depfile"
-  sed < "$tmpdepfile" -n -e 's% %\\ %g' -e '/^\(.*\)$/ s::\1\::p' >> "$depfile"
-  rm -f "$tmpdepfile"
-  ;;
-
-msvcmsys)
-  # This case exists only to let depend.m4 do its work.  It works by
-  # looking at the text of this script.  This case will never be run,
-  # since it is checked for above.
-  exit 1
-  ;;
-
-none)
-  exec "$@"
-  ;;
-
-*)
-  echo "Unknown depmode $depmode" 1>&2
-  exit 1
-  ;;
-esac
-
-exit 0
-
-# Local Variables:
-# mode: shell-script
-# sh-indentation: 2
-# eval: (add-hook 'write-file-hooks 'time-stamp)
-# time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
-# time-stamp-time-zone: "UTC"
-# time-stamp-end: "; # UTC"
-# End:
--- a/example.c
+++ b/example.c
@@ -2,10 +2,13 @@
 #if 0 /* in case someone actually tries to compile this */

 /* example.c - an example of using libpng
- * Last changed in libpng 1.5.7 [December 15, 2011]
- * Maintained 1998-2011 Glenn Randers-Pehrson
- * Maintained 1996, 1997 Andreas Dilger
- * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Maintained 1998-2014 Glenn Randers-Pehrson
+ * Maintained 1996, 1997 Andreas Dilger)
+ * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ * To the extent possible under law, the authors have waived
+ * all copyright and related or neighboring rights to this file.
+ * This work is published from: United States.
 */

 /* This is an example of how to use libpng to read and write PNG files.
@@ -13,8 +16,6 @@
 * read it, do so first.  This was designed to be a starting point of an
 * implementation.  This is not officially part of libpng, is hereby placed
 * in the public domain, and therefore does not require a copyright notice.
- * To the extent possible under law, the authors have waived all copyright and
- * related or neighboring rights to this file.
 *
 * This file does not currently compile, because it is missing certain
 * parts, like allocating memory to hold an image.  You will have to
@@ -23,11 +24,192 @@
 * see also the programs in the contrib directory.
 */

-#define _POSIX_SOURCE 1  /* libpng and zlib are POSIX-compliant.  You may
-                          * change this if your application uses non-POSIX
-                          * extensions. */
+/* The simple, but restricted, approach to reading a PNG file or data stream
+ * just requires two function calls, as in the following complete program.
+ * Writing a file just needs one function call, so long as the data has an
+ * appropriate layout.
+ *
+ * The following code reads PNG image data from a file and writes it, in a
+ * potentially new format, to a new file.  While this code will compile there is
+ * minimal (insufficient) error checking; for a more realistic version look at
+ * contrib/examples/pngtopng.c
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <png.h>
+#include <zlib.h>

-#include "png.h"
+int main(int argc, const char **argv)
+{
+   if (argc == 3)
+   {
+      png_image image; /* The control structure used by libpng */
+
+      /* Initialize the 'png_image' structure. */
+      memset(&image, 0, (sizeof image));
+      image.version = PNG_IMAGE_VERSION;
+
+      /* The first argument is the file to read: */
+      if (png_image_begin_read_from_file(&image, argv[1]) != 0)
+      {
+         png_bytep buffer;
+
+         /* Set the format in which to read the PNG file; this code chooses a
+          * simple sRGB format with a non-associated alpha channel, adequate to
+          * store most images.
+          */
+         image.format = PNG_FORMAT_RGBA;
+
+         /* Now allocate enough memory to hold the image in this format; the
+          * PNG_IMAGE_SIZE macro uses the information about the image (width,
+          * height and format) stored in 'image'.
+          */
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         /* If enough memory was available read the image in the desired format
+          * then write the result out to the new file.  'background' is not
+          * necessary when reading the image because the alpha channel is
+          * preserved; if it were to be removed, for example if we requested
+          * PNG_FORMAT_RGB, then either a solid background color would have to
+          * be supplied or the output buffer would have to be initialized to the
+          * actual background of the image.
+          *
+          * The fourth argument to png_image_finish_read is the 'row_stride' -
+          * this is the number of components allocated for the image in each
+          * row.  It has to be at least as big as the value returned by
+          * PNG_IMAGE_ROW_STRIDE, but if you just allocate space for the
+          * default, minimum, size using PNG_IMAGE_SIZE as above you can pass
+          * zero.
+          *
+          * The final argument is a pointer to a buffer for the colormap;
+          * colormaps have exactly the same format as a row of image pixels (so
+          * you choose what format to make the colormap by setting
+          * image.format).  A colormap is only returned if
+          * PNG_FORMAT_FLAG_COLORMAP is also set in image.format, so in this
+          * case NULL is passed as the final argument.  If you do want to force
+          * all images into an index/color-mapped format then you can use:
+          *
+          *    PNG_IMAGE_COLORMAP_SIZE(image)
+          *
+          * to find the maximum size of the colormap in bytes.
+          */
+         if (buffer != NULL &&
+            png_image_finish_read(&image, NULL/*background*/, buffer,
+               0/*row_stride*/, NULL/*colormap*/) != 0)
+         {
+            /* Now write the image out to the second argument.  In the write
+             * call 'convert_to_8bit' allows 16-bit data to be squashed down to
+             * 8 bits; this isn't necessary here because the original read was
+             * to the 8-bit format.
+             */
+            if (png_image_write_to_file(&image, argv[2], 0/*convert_to_8bit*/,
+               buffer, 0/*row_stride*/, NULL/*colormap*/) != 0)
+            {
+               /* The image has been written successfully. */
+               exit(0);
+            }
+         }
+
+         else
+         {
+            /* Calling png_free_image is optional unless the simplified API was
+             * not run to completion.  In this case if there wasn't enough
+             * memory for 'buffer' we didn't complete the read, so we must free
+             * the image:
+             */
+            if (buffer == NULL)
+               png_free_image(&image);
+
+            else
+               free(buffer);
+      }
+
+      /* Something went wrong reading or writing the image.  libpng stores a
+       * textual message in the 'png_image' structure:
+       */
+      fprintf(stderr, "pngtopng: error: %s\n", image.message);
+      exit (1);
+   }
+
+   fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n");
+   exit(1);
+}
+
+/* That's it ;-)  Of course you probably want to do more with PNG files than
+ * just converting them all to 32-bit RGBA PNG files; you can do that between
+ * the call to png_image_finish_read and png_image_write_to_file.  You can also
+ * ask for the image data to be presented in a number of different formats.  You
+ * do this by simply changing the 'format' parameter set before allocating the
+ * buffer.
+ *
+ * The format parameter consists of five flags that define various aspects of
+ * the image, you can simply add these together to get the format or you can use
+ * one of the predefined macros from png.h (as above):
+ *
+ * PNG_FORMAT_FLAG_COLOR: if set the image will have three color components per
+ *    pixel (red, green and blue), if not set the image will just have one
+ *    luminance (grayscale) component.
+ *
+ * PNG_FORMAT_FLAG_ALPHA: if set each pixel in the image will have an additional
+ *    alpha value; a linear value that describes the degree the image pixel
+ *    covers (overwrites) the contents of the existing pixel on the display.
+ *
+ * PNG_FORMAT_FLAG_LINEAR: if set the components of each pixel will be returned
+ *    as a series of 16-bit linear values, if not set the components will be
+ *    returned as a series of 8-bit values encoded according to the 'sRGB'
+ *    standard.  The 8-bit format is the normal format for images intended for
+ *    direct display, because almost all display devices do the inverse of the
+ *    sRGB transformation to the data they receive.  The 16-bit format is more
+ *    common for scientific data and image data that must be further processed;
+ *    because it is linear simple math can be done on the component values.
+ *    Regardless of the setting of this flag the alpha channel is always linear,
+ *    although it will be 8 bits or 16 bits wide as specified by the flag.
+ *
+ * PNG_FORMAT_FLAG_BGR: if set the components of a color pixel will be returned
+ *    in the order blue, then green, then red.  If not set the pixel components
+ *    are in the order red, then green, then blue.
+ *
+ * PNG_FORMAT_FLAG_AFIRST: if set the alpha channel (if present) precedes the
+ *    color or grayscale components.  If not set the alpha channel follows the
+ *    components.
+ *
+ * You do not have to read directly from a file.  You can read from memory or,
+ * on systems that support it, from a <stdio.h> FILE*.  This is controlled by
+ * the particular png_image_read_from_ function you call at the start.  Likewise
+ * on write you can write to a FILE* if your system supports it.  Check the
+ * macro PNG_STDIO_SUPPORTED to see if stdio support has been included in your
+ * libpng build.
+ *
+ * If you read 16-bit (PNG_FORMAT_FLAG_LINEAR) data you may need to write it in
+ * the 8-bit format for display.  You do this by setting the convert_to_8bit
+ * flag to 'true'.
+ *
+ * Don't repeatedly convert between the 8-bit and 16-bit forms.  There is
+ * significant data loss when 16-bit data is converted to the 8-bit encoding and
+ * the current libpng implementation of conversion to 16-bit is also
+ * significantly lossy.  The latter will be fixed in the future, but the former
+ * is unavoidable - the 8-bit format just doesn't have enough resolution.
+ */
+
+/* If your program needs more information from the PNG data it reads, or if you
+ * need to do more complex transformations, or minimize transformations, on the
+ * data you read, then you must use one of the several lower level libpng
+ * interfaces.
+ *
+ * All these interfaces require that you do your own error handling - your
+ * program must be able to arrange for control to return to your own code any
+ * time libpng encounters a problem.  There are several ways to do this, but the
+ * standard way is to use the ANSI-C (C90) <setjmp.h> interface to establish a
+ * return point within your own code.  You must do this if you do not use the
+ * simplified interface (above).
+ *
+ * The first step is to include the header files you need, including the libpng
+ * header file.  Include any standard headers and feature test macros your
+ * program requires before including png.h:
+ */
+#include <png.h>

 /* The png_jmpbuf() macro, used in error handling, became available in
  * libpng version 1.0.6.  If you want to be able to run your code with older
@@ -223,7 +405,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   /* Expand paletted or RGB images with transparency to full alpha channels
    * so the data will be available as RGBA quartets.
    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) != 0)
      png_set_tRNS_to_alpha(png_ptr);

   /* Set the background color to draw transparent and alpha images over.
@@ -235,7 +417,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */

   png_color_16 my_background, *image_background;

-   if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+   if (png_get_bKGD(png_ptr, info_ptr, &image_background) != 0)
      png_set_background(png_ptr, image_background,
                         PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
   else
@@ -259,9 +441,9 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   /* If we don't have another value */
   else
   {
-      screen_gamma = 2.2;  /* A good guess for a PC monitor in a dimly
-                              lit room */
-      screen_gamma = 1.7 or 1.0;  /* A good guess for Mac systems */
+      screen_gamma = PNG_DEFAULT_sRGB;  /* A good guess for a PC monitor
+                                           in a dimly lit room */
+      screen_gamma = PNG_GAMMA_MAC_18 or 1.0; /* Good guesses for Mac systems */
   }

   /* Tell libpng to handle the gamma conversion for you.  The final call
@@ -272,12 +454,12 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */

   int intent;

-   if (png_get_sRGB(png_ptr, info_ptr, &intent))
-      png_set_gamma(png_ptr, screen_gamma, 0.45455);
+   if (png_get_sRGB(png_ptr, info_ptr, &intent) != 0)
+      png_set_gamma(png_ptr, screen_gamma, PNG_DEFAULT_sRGB);
   else
   {
      double image_gamma;
-      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
+      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma) != 0)
         png_set_gamma(png_ptr, screen_gamma, image_gamma);
      else
         png_set_gamma(png_ptr, screen_gamma, 0.45455);
@@ -287,7 +469,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   /* Quantize RGB files down to 8 bit palette or reduce palettes
    * to the number of colors available on your screen.
    */
-   if (color_type & PNG_COLOR_MASK_COLOR)
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
   {
      int num_palette;
      png_colorp palette;
@@ -302,7 +484,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
            MAX_SCREEN_COLORS, NULL, 0);
      }
      /* This reduces the image to the palette supplied in the file */
-      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
+      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) != 0)
      {
         png_uint_16p histogram = NULL;

@@ -312,7 +494,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
                        max_screen_colors, histogram, 0);
      }
   }
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
+#endif /* READ_QUANTIZE */

   /* Invert monochrome files to have 0 as white and 1 as black */
   png_set_invert_mono(png_ptr);
@@ -321,7 +503,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
    * [0,65535] to the original [0,7] or [0,31], or whatever range the
    * colors were originally in:
    */
-   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT) != 0)
   {
      png_color_8p sig_bit_p;

@@ -330,7 +512,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   }

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

   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
@@ -350,7 +532,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
   number_passes = png_set_interlace_handling(png_ptr);
 #else
   number_passes = 1;
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
+#endif /* READ_INTERLACING */


   /* Optional call to gamma correct and add the background to the palette
@@ -549,7 +731,7 @@ row_callback(png_structp png_ptr, png_bytep new_row,
    * png_progressive_combine_row() passing in the new row and the
    * old row, as demonstrated above.  You can call this function for
    * NULL rows (it will just return) and for non-interlaced images
-    * (it just does the png_memcpy for you) if it will make the code
+    * (it just does the memcpy for you) if it will make the code
    * easier.  Thus, you can just do this for all cases:
    */

@@ -562,7 +744,7 @@ row_callback(png_structp png_ptr, png_bytep new_row,
    * to pass the current row as new_row, and the function will combine
    * the old row and the new row.
    */
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
+#endif /* READ_INTERLACING */
 }

 end_callback(png_structp png_ptr, png_infop info)
@@ -664,7 +846,7 @@ void write_png(char *file_name /* , ... other image information ... */)

   /* Set the palette if there is one.  REQUIRED for indexed-color images */
   palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH
-             * png_sizeof(png_color));
+             * (sizeof (png_color)));
   /* ... Set palette colors ... */
   png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH);
   /* You must not free palette here, because png_set_PLTE only makes a link to
@@ -695,25 +877,38 @@ void write_png(char *file_name /* , ... other image information ... */)
   png_set_gAMA(png_ptr, info_ptr, gamma);

   /* Optionally write comments into the image */
-   text_ptr[0].key = "Title";
-   text_ptr[0].text = "Mona Lisa";
-   text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
-   text_ptr[0].itxt_length = 0;
-   text_ptr[0].lang = NULL;
-   text_ptr[0].lang_key = NULL;
-   text_ptr[1].key = "Author";
-   text_ptr[1].text = "Leonardo DaVinci";
-   text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
-   text_ptr[1].itxt_length = 0;
-   text_ptr[1].lang = NULL;
-   text_ptr[1].lang_key = NULL;
-   text_ptr[2].key = "Description";
-   text_ptr[2].text = "<long text>";
-   text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
-   text_ptr[2].itxt_length = 0;
-   text_ptr[2].lang = NULL;
-   text_ptr[2].lang_key = NULL;
-   png_set_text(png_ptr, info_ptr, text_ptr, 3);
+   {
+      png_text text_ptr[3];
+
+      char key0[]="Title";
+      char text0[]="Mona Lisa";
+      text_ptr[0].key = key0;
+      text_ptr[0].text = text0;
+      text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
+      text_ptr[0].itxt_length = 0;
+      text_ptr[0].lang = NULL;
+      text_ptr[0].lang_key = NULL;
+
+      char key1[]="Author";
+      char text1[]="Leonardo DaVinci";
+      text_ptr[1].key = key1;
+      text_ptr[1].text = text1;
+      text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
+      text_ptr[1].itxt_length = 0;
+      text_ptr[1].lang = NULL;
+      text_ptr[1].lang_key = NULL;
+
+      char key2[]="Description";
+      char text2[]="<long text>";
+      text_ptr[2].key = key2;
+      text_ptr[2].text = text2;
+      text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
+      text_ptr[2].itxt_length = 0;
+      text_ptr[2].lang = NULL;
+      text_ptr[2].lang_key = NULL;
+
+      png_set_text(write_ptr, write_info_ptr, text_ptr, 3);
+   }

   /* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs */

@@ -737,7 +932,7 @@ void write_png(char *file_name /* , ... other image information ... */)
    */

   /* Once we write out the header, the compression type on the text
-    * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
+    * chunk gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
    * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
    * at the end.
    */
@@ -775,7 +970,7 @@ void write_png(char *file_name /* , ... other image information ... */)
   png_set_packswap(png_ptr);

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

   else
@@ -786,12 +981,16 @@ void write_png(char *file_name /* , ... other image information ... */)
    * use the first method if you aren't handling interlacing yourself.
    */
   png_uint_32 k, height, width;
-   png_byte image[height][width*bytes_per_pixel];
+
+   /* In this example, "image" is a one-dimensional array of bytes */
+   png_byte image[height*width*bytes_per_pixel];
+
   png_bytep row_pointers[height];

-   if (height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
+   if (height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
     png_error (png_ptr, "Image is too tall to process in memory");

+   /* Set up pointers into your "image" byte array */
   for (k = 0; k < height; k++)
     row_pointers[k] = image + k*width*bytes_per_pixel;

--- a/527
+++ b/527
@@ -1,527 +0,0 @@
-#!/bin/sh
-# install - install a program, script, or datafile
-
-scriptversion=2011-01-19.21; # UTC
-
-# This originates from X11R5 (mit/util/scripts/install.sh), which was
-# later released in X11R6 (xc/config/util/install.sh) with the
-# following copyright and license.
-#
-# Copyright (C) 1994 X Consortium
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to
-# deal in the Software without restriction, including without limitation the
-# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
-# sell copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in
-# all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-# X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
-# AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNEC-
-# TION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-# Except as contained in this notice, the name of the X Consortium shall not
-# be used in advertising or otherwise to promote the sale, use or other deal-
-# ings in this Software without prior written authorization from the X Consor-
-# tium.
-#
-#
-# FSF changes to this file are in the public domain.
-#
-# Calling this script install-sh is preferred over install.sh, to prevent
-# `make' implicit rules from creating a file called install from it
-# when there is no Makefile.
-#
-# This script is compatible with the BSD install script, but was written
-# from scratch.
-
-nl='
-'
-IFS=" ""	$nl"
-
-# set DOITPROG to echo to test this script
-
-# Don't use :- since 4.3BSD and earlier shells don't like it.
-doit=${DOITPROG-}
-if test -z "$doit"; then
-  doit_exec=exec
-else
-  doit_exec=$doit
-fi
-
-# Put in absolute file names if you don't have them in your path;
-# or use environment vars.
-
-chgrpprog=${CHGRPPROG-chgrp}
-chmodprog=${CHMODPROG-chmod}
-chownprog=${CHOWNPROG-chown}
-cmpprog=${CMPPROG-cmp}
-cpprog=${CPPROG-cp}
-mkdirprog=${MKDIRPROG-mkdir}
-mvprog=${MVPROG-mv}
-rmprog=${RMPROG-rm}
-stripprog=${STRIPPROG-strip}
-
-posix_glob='?'
-initialize_posix_glob='
-  test "$posix_glob" != "?" || {
-    if (set -f) 2>/dev/null; then
-      posix_glob=
-    else
-      posix_glob=:
-    fi
-  }
-'
-
-posix_mkdir=
-
-# Desired mode of installed file.
-mode=0755
-
-chgrpcmd=
-chmodcmd=$chmodprog
-chowncmd=
-mvcmd=$mvprog
-rmcmd="$rmprog -f"
-stripcmd=
-
-src=
-dst=
-dir_arg=
-dst_arg=
-
-copy_on_change=false
-no_target_directory=
-
-usage="\
-Usage: $0 [OPTION]... [-T] SRCFILE DSTFILE
-   or: $0 [OPTION]... SRCFILES... DIRECTORY
-   or: $0 [OPTION]... -t DIRECTORY SRCFILES...
-   or: $0 [OPTION]... -d DIRECTORIES...
-
-In the 1st form, copy SRCFILE to DSTFILE.
-In the 2nd and 3rd, copy all SRCFILES to DIRECTORY.
-In the 4th, create DIRECTORIES.
-
-Options:
-     --help     display this help and exit.
-     --version  display version info and exit.
-
-  -c            (ignored)
-  -C            install only if different (preserve the last data modification time)
-  -d            create directories instead of installing files.
-  -g GROUP      $chgrpprog installed files to GROUP.
-  -m MODE       $chmodprog installed files to MODE.
-  -o USER       $chownprog installed files to USER.
-  -s            $stripprog installed files.
-  -t DIRECTORY  install into DIRECTORY.
-  -T            report an error if DSTFILE is a directory.
-
-Environment variables override the default commands:
-  CHGRPPROG CHMODPROG CHOWNPROG CMPPROG CPPROG MKDIRPROG MVPROG
-  RMPROG STRIPPROG
-"
-
-while test $# -ne 0; do
-  case $1 in
-    -c) ;;
-
-    -C) copy_on_change=true;;
-
-    -d) dir_arg=true;;
-
-    -g) chgrpcmd="$chgrpprog $2"
-	shift;;
-
-    --help) echo "$usage"; exit $?;;
-
-    -m) mode=$2
-	case $mode in
-	  *' '* | *'	'* | *'
-'*	  | *'*'* | *'?'* | *'['*)
-	    echo "$0: invalid mode: $mode" >&2
-	    exit 1;;
-	esac
-	shift;;
-
-    -o) chowncmd="$chownprog $2"
-	shift;;
-
-    -s) stripcmd=$stripprog;;
-
-    -t) dst_arg=$2
-	# Protect names problematic for `test' and other utilities.
-	case $dst_arg in
-	  -* | [=\(\)!]) dst_arg=./$dst_arg;;
-	esac
-	shift;;
-
-    -T) no_target_directory=true;;
-
-    --version) echo "$0 $scriptversion"; exit $?;;
-
-    --)	shift
-	break;;
-
-    -*)	echo "$0: invalid option: $1" >&2
-	exit 1;;
-
-    *)  break;;
-  esac
-  shift
-done
-
-if test $# -ne 0 && test -z "$dir_arg$dst_arg"; then
-  # When -d is used, all remaining arguments are directories to create.
-  # When -t is used, the destination is already specified.
-  # Otherwise, the last argument is the destination.  Remove it from $@.
-  for arg
-  do
-    if test -n "$dst_arg"; then
-      # $@ is not empty: it contains at least $arg.
-      set fnord "$@" "$dst_arg"
-      shift # fnord
-    fi
-    shift # arg
-    dst_arg=$arg
-    # Protect names problematic for `test' and other utilities.
-    case $dst_arg in
-      -* | [=\(\)!]) dst_arg=./$dst_arg;;
-    esac
-  done
-fi
-
-if test $# -eq 0; then
-  if test -z "$dir_arg"; then
-    echo "$0: no input file specified." >&2
-    exit 1
-  fi
-  # It's OK to call `install-sh -d' without argument.
-  # This can happen when creating conditional directories.
-  exit 0
-fi
-
-if test -z "$dir_arg"; then
-  do_exit='(exit $ret); exit $ret'
-  trap "ret=129; $do_exit" 1
-  trap "ret=130; $do_exit" 2
-  trap "ret=141; $do_exit" 13
-  trap "ret=143; $do_exit" 15
-
-  # Set umask so as not to create temps with too-generous modes.
-  # However, 'strip' requires both read and write access to temps.
-  case $mode in
-    # Optimize common cases.
-    *644) cp_umask=133;;
-    *755) cp_umask=22;;
-
-    *[0-7])
-      if test -z "$stripcmd"; then
-	u_plus_rw=
-      else
-	u_plus_rw='% 200'
-      fi
-      cp_umask=`expr '(' 777 - $mode % 1000 ')' $u_plus_rw`;;
-    *)
-      if test -z "$stripcmd"; then
-	u_plus_rw=
-      else
-	u_plus_rw=,u+rw
-      fi
-      cp_umask=$mode$u_plus_rw;;
-  esac
-fi
-
-for src
-do
-  # Protect names problematic for `test' and other utilities.
-  case $src in
-    -* | [=\(\)!]) src=./$src;;
-  esac
-
-  if test -n "$dir_arg"; then
-    dst=$src
-    dstdir=$dst
-    test -d "$dstdir"
-    dstdir_status=$?
-  else
-
-    # Waiting for this to be detected by the "$cpprog $src $dsttmp" command
-    # might cause directories to be created, which would be especially bad
-    # if $src (and thus $dsttmp) contains '*'.
-    if test ! -f "$src" && test ! -d "$src"; then
-      echo "$0: $src does not exist." >&2
-      exit 1
-    fi
-
-    if test -z "$dst_arg"; then
-      echo "$0: no destination specified." >&2
-      exit 1
-    fi
-    dst=$dst_arg
-
-    # If destination is a directory, append the input filename; won't work
-    # if double slashes aren't ignored.
-    if test -d "$dst"; then
-      if test -n "$no_target_directory"; then
-	echo "$0: $dst_arg: Is a directory" >&2
-	exit 1
-      fi
-      dstdir=$dst
-      dst=$dstdir/`basename "$src"`
-      dstdir_status=0
-    else
-      # Prefer dirname, but fall back on a substitute if dirname fails.
-      dstdir=`
-	(dirname "$dst") 2>/dev/null ||
-	expr X"$dst" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
-	     X"$dst" : 'X\(//\)[^/]' \| \
-	     X"$dst" : 'X\(//\)$' \| \
-	     X"$dst" : 'X\(/\)' \| . 2>/dev/null ||
-	echo X"$dst" |
-	    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
-		   s//\1/
-		   q
-		 }
-		 /^X\(\/\/\)[^/].*/{
-		   s//\1/
-		   q
-		 }
-		 /^X\(\/\/\)$/{
-		   s//\1/
-		   q
-		 }
-		 /^X\(\/\).*/{
-		   s//\1/
-		   q
-		 }
-		 s/.*/./; q'
-      `
-
-      test -d "$dstdir"
-      dstdir_status=$?
-    fi
-  fi
-
-  obsolete_mkdir_used=false
-
-  if test $dstdir_status != 0; then
-    case $posix_mkdir in
-      '')
-	# Create intermediate dirs using mode 755 as modified by the umask.
-	# This is like FreeBSD 'install' as of 1997-10-28.
-	umask=`umask`
-	case $stripcmd.$umask in
-	  # Optimize common cases.
-	  *[2367][2367]) mkdir_umask=$umask;;
-	  .*0[02][02] | .[02][02] | .[02]) mkdir_umask=22;;
-
-	  *[0-7])
-	    mkdir_umask=`expr $umask + 22 \
-	      - $umask % 100 % 40 + $umask % 20 \
-	      - $umask % 10 % 4 + $umask % 2
-	    `;;
-	  *) mkdir_umask=$umask,go-w;;
-	esac
-
-	# With -d, create the new directory with the user-specified mode.
-	# Otherwise, rely on $mkdir_umask.
-	if test -n "$dir_arg"; then
-	  mkdir_mode=-m$mode
-	else
-	  mkdir_mode=
-	fi
-
-	posix_mkdir=false
-	case $umask in
-	  *[123567][0-7][0-7])
-	    # POSIX mkdir -p sets u+wx bits regardless of umask, which
-	    # is incompatible with FreeBSD 'install' when (umask & 300) != 0.
-	    ;;
-	  *)
-	    tmpdir=${TMPDIR-/tmp}/ins$RANDOM-$$
-	    trap 'ret=$?; rmdir "$tmpdir/d" "$tmpdir" 2>/dev/null; exit $ret' 0
-
-	    if (umask $mkdir_umask &&
-		exec $mkdirprog $mkdir_mode -p -- "$tmpdir/d") >/dev/null 2>&1
-	    then
-	      if test -z "$dir_arg" || {
-		   # Check for POSIX incompatibilities with -m.
-		   # HP-UX 11.23 and IRIX 6.5 mkdir -m -p sets group- or
-		   # other-writeable bit of parent directory when it shouldn't.
-		   # FreeBSD 6.1 mkdir -m -p sets mode of existing directory.
-		   ls_ld_tmpdir=`ls -ld "$tmpdir"`
-		   case $ls_ld_tmpdir in
-		     d????-?r-*) different_mode=700;;
-		     d????-?--*) different_mode=755;;
-		     *) false;;
-		   esac &&
-		   $mkdirprog -m$different_mode -p -- "$tmpdir" && {
-		     ls_ld_tmpdir_1=`ls -ld "$tmpdir"`
-		     test "$ls_ld_tmpdir" = "$ls_ld_tmpdir_1"
-		   }
-		 }
-	      then posix_mkdir=:
-	      fi
-	      rmdir "$tmpdir/d" "$tmpdir"
-	    else
-	      # Remove any dirs left behind by ancient mkdir implementations.
-	      rmdir ./$mkdir_mode ./-p ./-- 2>/dev/null
-	    fi
-	    trap '' 0;;
-	esac;;
-    esac
-
-    if
-      $posix_mkdir && (
-	umask $mkdir_umask &&
-	$doit_exec $mkdirprog $mkdir_mode -p -- "$dstdir"
-      )
-    then :
-    else
-
-      # The umask is ridiculous, or mkdir does not conform to POSIX,
-      # or it failed possibly due to a race condition.  Create the
-      # directory the slow way, step by step, checking for races as we go.
-
-      case $dstdir in
-	/*) prefix='/';;
-	[-=\(\)!]*) prefix='./';;
-	*)  prefix='';;
-      esac
-
-      eval "$initialize_posix_glob"
-
-      oIFS=$IFS
-      IFS=/
-      $posix_glob set -f
-      set fnord $dstdir
-      shift
-      $posix_glob set +f
-      IFS=$oIFS
-
-      prefixes=
-
-      for d
-      do
-	test X"$d" = X && continue
-
-	prefix=$prefix$d
-	if test -d "$prefix"; then
-	  prefixes=
-	else
-	  if $posix_mkdir; then
-	    (umask=$mkdir_umask &&
-	     $doit_exec $mkdirprog $mkdir_mode -p -- "$dstdir") && break
-	    # Don't fail if two instances are running concurrently.
-	    test -d "$prefix" || exit 1
-	  else
-	    case $prefix in
-	      *\'*) qprefix=`echo "$prefix" | sed "s/'/'\\\\\\\\''/g"`;;
-	      *) qprefix=$prefix;;
-	    esac
-	    prefixes="$prefixes '$qprefix'"
-	  fi
-	fi
-	prefix=$prefix/
-      done
-
-      if test -n "$prefixes"; then
-	# Don't fail if two instances are running concurrently.
-	(umask $mkdir_umask &&
-	 eval "\$doit_exec \$mkdirprog $prefixes") ||
-	  test -d "$dstdir" || exit 1
-	obsolete_mkdir_used=true
-      fi
-    fi
-  fi
-
-  if test -n "$dir_arg"; then
-    { test -z "$chowncmd" || $doit $chowncmd "$dst"; } &&
-    { test -z "$chgrpcmd" || $doit $chgrpcmd "$dst"; } &&
-    { test "$obsolete_mkdir_used$chowncmd$chgrpcmd" = false ||
-      test -z "$chmodcmd" || $doit $chmodcmd $mode "$dst"; } || exit 1
-  else
-
-    # Make a couple of temp file names in the proper directory.
-    dsttmp=$dstdir/_inst.$$_
-    rmtmp=$dstdir/_rm.$$_
-
-    # Trap to clean up those temp files at exit.
-    trap 'ret=$?; rm -f "$dsttmp" "$rmtmp" && exit $ret' 0
-
-    # Copy the file name to the temp name.
-    (umask $cp_umask && $doit_exec $cpprog "$src" "$dsttmp") &&
-
-    # and set any options; do chmod last to preserve setuid bits.
-    #
-    # If any of these fail, we abort the whole thing.  If we want to
-    # ignore errors from any of these, just make sure not to ignore
-    # errors from the above "$doit $cpprog $src $dsttmp" command.
-    #
-    { test -z "$chowncmd" || $doit $chowncmd "$dsttmp"; } &&
-    { test -z "$chgrpcmd" || $doit $chgrpcmd "$dsttmp"; } &&
-    { test -z "$stripcmd" || $doit $stripcmd "$dsttmp"; } &&
-    { test -z "$chmodcmd" || $doit $chmodcmd $mode "$dsttmp"; } &&
-
-    # If -C, don't bother to copy if it wouldn't change the file.
-    if $copy_on_change &&
-       old=`LC_ALL=C ls -dlL "$dst"	2>/dev/null` &&
-       new=`LC_ALL=C ls -dlL "$dsttmp"	2>/dev/null` &&
-
-       eval "$initialize_posix_glob" &&
-       $posix_glob set -f &&
-       set X $old && old=:$2:$4:$5:$6 &&
-       set X $new && new=:$2:$4:$5:$6 &&
-       $posix_glob set +f &&
-
-       test "$old" = "$new" &&
-       $cmpprog "$dst" "$dsttmp" >/dev/null 2>&1
-    then
-      rm -f "$dsttmp"
-    else
-      # Rename the file to the real destination.
-      $doit $mvcmd -f "$dsttmp" "$dst" 2>/dev/null ||
-
-      # The rename failed, perhaps because mv can't rename something else
-      # to itself, or perhaps because mv is so ancient that it does not
-      # support -f.
-      {
-	# Now remove or move aside any old file at destination location.
-	# We try this two ways since rm can't unlink itself on some
-	# systems and the destination file might be busy for other
-	# reasons.  In this case, the final cleanup might fail but the new
-	# file should still install successfully.
-	{
-	  test ! -f "$dst" ||
-	  $doit $rmcmd -f "$dst" 2>/dev/null ||
-	  { $doit $mvcmd -f "$dst" "$rmtmp" 2>/dev/null &&
-	    { $doit $rmcmd -f "$rmtmp" 2>/dev/null; :; }
-	  } ||
-	  { echo "$0: cannot unlink or rename $dst" >&2
-	    (exit 1); exit 1
-	  }
-	} &&
-
-	# Now rename the file to the real destination.
-	$doit $mvcmd "$dsttmp" "$dst"
-      }
-    fi || exit 1
-
-    trap '' 0
-  fi
-done
-
-# Local variables:
-# eval: (add-hook 'write-file-hooks 'time-stamp)
-# time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
-# time-stamp-time-zone: "UTC"
-# time-stamp-end: "; # UTC"
-# End:
--- a/libpng-config.in
+++ b/libpng-config.in
--- a/Show More
+++ b/Show More