FWIW, the sdl2 egg fails to build with gcc-4.6:
In file included from sdl2-internals.c:14:0:
lib/sdl2-internals/custom-functions.c: In function
‘chickenSDL2_RotateSurface90’:
lib/sdl2-internals/custom-functions.c:212:3: error: ‘for’ loop initial
declarations are only allowed in C99 mode
lib/sdl2-internals/custom-functions.c:212:3: note: use option -std=c99 or
-std=gnu99 to compile your code
lib/sdl2-internals/custom-functions.c:213:5: error: ‘for’ loop initial
declarations are only allowed in C99 mode
lib/sdl2-internals/custom-functions.c: In function
‘chickenSDL2_FlipSurface’:
lib/sdl2-internals/custom-functions.c:267:3: error: ‘for’ loop initial
declarations are only allowed in C99 mode
lib/sdl2-internals/custom-functions.c:268:5: error: ‘for’ loop initial
declarations are only allowed in C99 mode
Building with gcc-5 instead worked fine. The sdl2-image project didn't
have this problem.