[libpng15] Changed AM_CONFIG_HEADER(config.h) to AC_CONFIG_HEADERS([config.h])

in configure.ac
[libpng15] De-configured build fixes to make a range of deconfiguration options

(such as switching off read or write support) work in more cases.  Also
upgraded pngtest and pngvalid to the libpng 1.6 versions (with some
modifications) which provide more extensive testing.  Replaced pngtest.png
because pngtest writes the ancillary chunks in a different order.
[libpng15] Updated pngvalid.c from libpng16
[libpng15] Bump version to 1.5.14beta08
[libpng15] Check validity of "num_unknowns" parameter

of png_set_unknown_chunks().
[libpng15] Bump version to 1.5.14beta09
[libpng15] Imported from libpng-1.5.14rc01.tar
[libpng15] Change info_ptr->unknown_chunks_num to type png_uint_32

and test against INT_MAX instead of UINT_MAX in pngset.c
[libpng15] Revised test for validity of "num_unknowns" to eliminate compiler

warnings.
[libpng15] Bump version to 1.5.14rc03
[libpng15] Check validity of "nentries" parameter of png_set_sPLT().
[libpng15] Check validity of "nentries" parameter of png_set_sPLT().

and check validity of "num_text" parameter of png_set_text_2().
[libpng15] Imported from libpng-1.5.14rc03.tar
[libpng15] Removed an obsolete line from the manual.
[libpng15] Imported from libpng-1.5.14.tar
[libpng15] Bump version to 1.5.15beta01
[libpng15] Enabled renaming of the extern (but not DLL exported) ARM filter

functions.  Also enabled inclusion of pngpriv.h in non-C files by preventing
C/C++ specific definitions if PNG_VERSION_INFO_ONLY is defined.
[libpng15] Added documentation of new png_get_palette_max() function.
[libpng15] Imported from libpng-1.5.15beta01.tar
[libpng15] Bump version to 1.5.15beta02