Log Message:
Update to 1.2.19:

version 1.2.19beta1 [May 18, 2007]
  Changed "const static" to "static PNG_CONST" everywhere, \ 
mostly undoing
    change of libpng-1.2.17beta2.  Changed other "const" to \ 
"PNG_CONST"
  Changed some handling of unused parameters, to avoid compiler warnings.
    "if (unused == NULL) return;" becomes "unused = unused".

version 1.2.19beta2 [May 18, 2007]
  Only use the valid bits of tRNS value in png_do_expand() (Brian Cartier)

version 1.2.19beta3 [May 19, 2007]
  Add some "png_byte" typecasts in png_check_keyword() and write new_key
  instead of key in zTXt chunk (Kevin Ryde).

version 1.2.19beta4 [May 21, 2007]
  Add png_snprintf() function and use it in place of sprint() for improved
    defense against buffer overflows.

version 1.2.19beta5 [May 21, 2007]
  Fixed png_handle_tRNS() to only use the valid bits of tRNS value.
  Changed handling of more unused parameters, to avoid compiler warnings.
  Removed some PNG_CONST in pngwutil.c to avoid compiler warnings.

version 1.2.19beta6 [May 22, 2007]
  Added some #ifdef PNG_MMX_CODE_SUPPORTED where needed in pngvcrd.c
  Added a special "_MSC_VER" case that defines png_snprintf to _snprintf

version 1.2.19beta7 [May 22, 2007]
  Squelched png_squelch_warnings() in pnggccrd.c and added an
    #ifdef PNG_MMX_CODE_SUPPORTED block around the declarations that caused
    the warnings that png_squelch_warnings was squelching.

version 1.2.19beta8 [May 22, 2007]
  Removed __MMX__ from test in pngconf.h.

version 1.2.19beta9 [May 23, 2007]
  Made png_squelch_warnings() available via PNG_SQUELCH_WARNINGS macro.
  Revised png_squelch_warnings() so it might work.
  Updated makefile.sgcc and makefile.solaris; added makefile.solaris-x86.

version 1.2.19beta10 [May 24, 2007]
  Resquelched png_squelch_warnings(), use "__attribute__((used))" instead.

version 1.2.19beta11 [May 28, 2007]
  Return 0 from png_get_sPLT() and png_get_unknown_chunks() if png_ptr is NULL;
    changed three remaining instances of png_strcpy() to png_strncpy() (David
    Hill).
  Make test for NULL row_buf at the beginning of png_do_read_transformations
    unconditional.

version 1.2.19beta12 [May 28, 2007]
  Revised pnggccrd.c.

version 1.2.19beta13 [June 14, 2007]
  Prefer PNG_USE_PNGVCRD when _MSC_VER is defined in pngconf.h

version 1.2.19beta14 [June 16, 2007]
  Fix bug with handling of 16-bit transparency, introduced in 1.2.19beta2

version 1.2.19beta15 [June 17, 2007]
  Revised pnggccrd.c.

version 1.2.19beta16 [June 18, 2007]
  Revised pnggccrd.c again.
  Updated contrib/gregbook.
  Changed '#include "pnggccrd.c"' to 'include \ 
"$srcdir/pnggccrd.c"'
    in configure.ac

version 1.2.19beta17 [June 19, 2007]
  Revised many of the makefiles, to set -DPNG_NO_MMX_CODE where needed
    and to not use -O3 unless -DPNG_NO_MMX_CODE is also set.

version 1.2.19beta18 [June 23, 2007]
  Replaced some C++ style comments with C style comments in pnggccrd.c.
  Copied optimized C code from pnggccrd.c to pngrutil.c, removed dependency
    on pnggccrd.o from many makefiles.
  Added sl and dylib to list of extensions be installed by Makefile.am

version 1.2.19beta19 [June 28, 2007]
  Fixed testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN in pngrtran.c
  More cleanup of pnggccrd.c and pngvcrd.c

version 1.2.19beta20 [June 29, 2007]
  Rebuilt Makefile.in and configure using libtool-1.5.24.
  Fixed typo in pnggccrd.c

version 1.2.19beta21 [June 30, 2007]
  More revision of pnggccrd.c
  Added "test" target to Makefile.in and Makefile.am

version 1.2.19beta22 [July 3, 2007]
  Added info about pngrutil/pnggccrd/pngvcrd to png_get_header_version()
  Fix type definition of dummy_value_a, b in pnggccrd.c

version 1.2.19beta23 [July 10, 2007]
  Revert change to type definition of dummy_value_a, b in pnggccrd.c
  Make sure __PIC__ is defined in pnggccrd.c when PIC is defined.
  Require gcc-4.1 or better to use PNG_HAVE_MMX_FILTER_ROW on x86_64 platforms

version 1.2.19beta24 [July 14, 2007]
  Added PNG_NO_READ_FILTER, PNG_NO_WRITE_FILTER, PNG_NO_WARNING macros.
  Added contrib/pngminim to demonstrate building minimal encoder and decoder

version 1.2.19beta25 [July 15, 2007]
  Removed the new PNG_NO_READ_FILTER macro since it would make the library
    unable to read valid PNG files, and filtering is at the heart of the
    PNG format.

version 1.2.19beta26 [July 16, 2007]
  Changed "png_free(str)" to "png_free(png_ptr,str)" in \ 
pngrutil.c WinCE
    code (Yves Piguet).  This bug was introduced in libpng-1.2.14.
  Updated scripts/CMakeLists.txt
  Relocated a misplaced #endif in pnggccrd.c

version 1.2.19beta27 [July 17, 2007]
  Fixed incorrect stride and number of bytes copied (was 4 instead of
    6 bytes) in the cleanup loop of pnggccrd.c and pngvcrd.c for handling
    the end of 48-bit interlaced rows (Glenn R-P).

version 1.2.19beta28 [July 19, 2007]
  Removed requirement for gcc-4.1 or better to use PNG_HAVE_MMX_FILTER_ROW
    on x86_64 platforms
  Added png_warning() in pngrutil.c for short iCCP, iTXt, sPLT, or zTXT chunks.
  Revised pngtest.c so warnings are displayed regardless of PNG_NO_STDIO.

version 1.2.19beta29 [July 20, 2007]
  Fix typo in pnggccrd.c (%%eax should be %%ax in secondloop48)

version 1.2.19beta30 [July 26, 2007]
  Revised pnggccrd.c

version 1.2.19beta31 [July 27, 2007]
  Fix typos in pnggccrd.c

version 1.0.27rc1 and 1.2.19rc1 [July 31, 2007]
  Disable PNG_MMX_CODE_SUPPORTED when PNG_ASSEMBLER_CODE_SUPPORTED is off.
  Enable PNG_MMX_READ_FILTER_* by default, except when gcc-3.x is being
    used (they were inadvertently disabled in libpng-1.2.19beta23).
  Fix some debugging statements in pnggccrd.c and pngrutil.c
  Added information about disabling the MMX code in libpng documentation.

version 1.0.27rc2 and 1.2.19rc2 [August 4, 2007]
  Removed some "#if 0" blocks.
  Made a global struct local in pngvcrd.c to make it thread safe.
  Issue a png_error() if application attempts to transform a row tht
    has not been initialized.

version 1.0.27rc3 and 1.2.19rc3 [August 9, 2007]
  Slightly revised pngvcrd.c

version 1.0.27rc4 and 1.2.19rc4 [August 9, 2007]
  Revised pnggccrd.c debugging change of rc1, which was broken.
  Revised scripts/CMakeLists.txt
  Change default to PNG_NO_GLOBAL_ARRAYS for MSVC.
  Turn off PNG_FLAG_ROW_INIT flag when setting transforms that expand pixels.

version 1.0.27rc5 and 1.2.19rc5 [August 10, 2007]
  Fix typo (missing '"') in pnggccrd.c
  Revise handling of png_strtod in recent versions of WINCE

version 1.0.27rc6 and 1.2.19rc6 [August 15, 2007]
  Fix typo (missing ',') in contrib/gregbook/readpng2.c
  Undid row initialization error exit added to rc2 and rc4.

version 1.0.27 and 1.2.19 [August 18, 2007]
  Conditionally restored row initialization error exit.