Do not rely on INT_MAX in png.h

At a certain step in the configuration process, `gcc -Wundef`
complained about using `INT_MAX` without a definition in png.h,
which is easily fixable with an include.

We would rather not add any extra dependencies to png.h, however,
so we use some unsigned int arithmetic magic instead.
This commit is contained in:
Cosmin Truta 2024-01-12 01:12:08 +02:00
parent b3521c60af
commit 6b241f3786

2
png.h
View File

@ -849,7 +849,7 @@ PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
/* Added to libpng-1.5.4 */
#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
#if INT_MAX >= 0x8000 /* else this might break */
#if ~0U > 0xffffU /* or else this might break on a 16-bit machine */
#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
#endif