libpng-1.6.17

[Fernando de Oliveira]

​http://downloads.sourceforge.net/libpng/libpng-1.6.17.tar.xz

​http://downloads.sourceforge.net/libpng-apng/libpng-1.6.17-apng.patch.gz

​http://sourceforge.net/p/png-mng/mailman/message/33646547/

Libpng-1.6.17 Changes since the last public release (1.6.16):

  Removed duplicate PNG_SAFE_LIMITS_SUPPORTED handling from pngconf.h
  Corrected the width limit calculation in png_check_IHDR().
  Removed user limits from pngfix. Also pass NULL pointers to
    png_read_row to skip the unnecessary row de-interlace stuff.
  Added testing of png_set_packing() to pngvalid.c
  Regenerated configure scripts in the *.tar distributions with
    libtool-2.4.4
  Implement previously untested cases of libpng transforms in pngvalid.c
  Fixed byte order in 2-byte filler, in png_do_read_filler().
  Made the check for out-of-range values in png_set_tRNS() detect
    values that are exactly 2^bit_depth, and work on 16-bit platforms.
  Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
  Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
    pngset.c to avoid warnings about dead code.
  Do not build png_product2() when it is unused.
  Display user limits in the output from pngtest.
  Eliminated the PNG_SAFE_LIMITS macro and restored the 1-million-column
    and 1-million-row default limits in pnglibconf.dfa, that can be reset
    by the user at build time or run time.  This provides a more robust
    defense against DOS and as-yet undiscovered overflows.
  Added PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED macro, on by default.
  Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
  Rebuilt configure scripts with automake-1.15 and libtool-2.4.6
  Moved png_set_filter() prototype into a PNG_WRITE_SUPPORTED block
    of png.h.
  Avoid runtime checks when converting integer to png_byte with
    Visual Studio (Sergey Kosarevsky)
  Removed some comments that the configure script did not handle
    properly from scripts/pnglibconf.dfa and pnglibconf.h.prebuilt.
  Free the unknown_chunks structure even when it contains no data.
  Updated CMakeLists.txt to add OSX framework, change YES/NO to ON/OFF
    for consistency, and remove some useless tests (Alexey Petruchik).
  Remove pnglibconf.h, pnglibconf.c, pnglibconf.pre, pnglibconf.dfn,
    and pnglibconf.out instead of pnglibconf.* in "make clean" (Cosmin).
  Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
    value was wrong.  It's not clear if this affected the final stored
    value; in the obvious code path the upper and lower 8-bits of the
    alpha value were identical and the alpha was truncated to 8-bits
    rather than dividing by 257 (John Bowler).

[Fernando de Oliveira]

Fixed at r15807.