Seperate glX from HAVE_OPENGL, for platforms that have both an X server and a more official way to do OpenGL, explicitly check for glX on Mac OS X, and use SDL_LoadObject for platforms that have glX but don't have dlopen().

/* Include the SDL main definition header */
#include "SDL_main.h"

#ifdef main
#undef main
int main(int argc, char *argv[])
{
	return(SDL_main(argc, argv));
}
#else
/* Nothing to do on this platform */;
#endif