_ISOC99_SOURCE     76 contrib/libtests/makepng.c #define _ISOC99_SOURCE /* for strtoull */
_ISOC99_SOURCE     23 contrib/libtests/pngvalid.c #define _ISOC99_SOURCE 1 /* For floating point */
_ISOC99_SOURCE     21 contrib/libtests/tarith.c #define _ISOC99_SOURCE 1
_ISOC99_SOURCE     13 contrib/tools/cvtcolor.c #define _ISOC99_SOURCE 1