[SDL] Setting environment variable SDL_VIDEODRIVER in win32

[Mike Harris]

I normally use gcc, but I'm trying to port my SDL game to windows. I don't 
want to use winlib or whatever it is, I want to use directx. In gcc, I just 
ues setenv("SDL_VIDEODRIVER", "dga", 1) to set it, but this doesn't seem to 
work in Visual C++ 6.0. Is there just a library I'm not including? I want 
it to set it at runtime too, not prior.