[SDL] fast int's in 1.3?

[Antonio SJ Musumeci]

Looking at SDL_stdinc.h in SDL 1.3... I'm not seeing anything like 
stdint.h's int_fast*_t. I think it'd be nice to provide something like 
that. I understand you ccould use "int" but it'd be nice to have data 
types consistent within SDL. If you just want an integer but don't care 
the size because you know it's a within a reasonable range and are more 
worried about speed.