[SDL] warning with HAVE_VSNPRINTF

[Erick Tryzelaar]

Hello,

So I'm running into an issue where I have two libraries trying to define 
HAVE_VSNPRINTF in their header files, with sdl being one of them 
(SDL_config.h on 10.4). This is causing some warnings to be raised. It's 
suggested in that file that we can comment out the "HAVE_LIBC", but I 
can't do that if I'm going to use the system's version of sdl. Would it 
be possible to put a guard in around the HAVE_LIBC to check if it's 
already been defined to 0, and if so, not to define the rest of libc 
definitions? This would let me easily work around this problem from my 
code. Is there any chance that this can happen? Thanks!

-e