libpng needs update on x86_64

[Torbjörn Rathsman]

Libpng needs to be updated to a later version than version 1.2 on x86_64. The reason is that version 1.2 assumes sizeof(unsigned long int)==4, which is not true on Linux x86_64

Message from GCC:

error: cannot convert 'uint32_t* {aka unsigned int*}' to 'png_uint_32* {aka long unsigned int*}' for argument '3' to 'png_uint_32 png_get_pHYs(png_structp, png_infop, png_uint_32*, png_uint_32*, int*)'
     , &res_x, &res_y,&unit);

In version 1.6 (I use that version when compiling on windows)

#if INT_MIN < -2147483646 && INT_MAX > 2147483646
   typedef int png_int_32;
#elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646
   typedef long int png_int_32;
#else
# error "libpng requires a signed 32 bit (or more) type"
#endif

#if UINT_MAX > 4294967294
   typedef unsigned int png_uint_32;
#elif ULONG_MAX > 4294967294
   typedef unsigned long int png_uint_32;
#else
# error "libpng requires an unsigned 32 bit (or more) type"
#endif

Clearly, this bug is fixed in version 1.6.

I could install my own libpng, but since this is a very central library I feel that it could be risky and I do not have time to recompile the hole system just for an old library. Suggestion: Fix this for version 14.10 (it strange that a newer libpng did not enter 14.04 LTS)

[Sebastien Bacher (seb128)]

that's the version in Debian as well, https://packages.qa.debian.org/libp/libpng.html

[Torbjörn Rathsman (milasudril)]

The present typedef change would really break the ABI on x86_64 so the entire system needs to be compiled with the new header.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.