SDL_GetAppState() correction when toggling fullscreen on OSX.
Patch by me to address this comment on the SDL mailing list:
"There appears to be a serious bug with SDL_GetAppState on OS X (10.3.9). When
first running in windowed mode and then switching to full screen mode by
calling SDL_SetVideoMode, SDL_GetAppState returns 4 (SDL_APPACTIVE) instead of
7 (SDL_APPMOUSEFOCUS | SDL_APPINPUTFOCUS | SDL_APPACTIVE). However, the SDL
application clearly does have the keyboard focus, since it is able to receive
keyboard events."
--ryan.