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().

The test programs in this directory tree are for demonstrating and
testing the functionality of the SDL library, and are placed in the
public domain.

October 28, 1997
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	Sam Lantinga				(slouken@libsdl.org)