Renamed functions and structures to GLES (rather than GL) to avoid confusion with the OpenGL renderer, which prior used the same names. Removed references to GL_IMG_texture_format_BGRA8888, which will not be supported here. Made it so renderer no longer caches texture filter mode, because I think that is actually bound to specific textures, so we'd need to cache the currently bound texture too ... I don't want to go through that trouble. DOES cache blend function though.

The reason these libraries are built outside of the standard XFree86
tree is so that they can be linked as shared object code directly into
SDL without causing any symbol collisions with code in the application.

You can't link static library code into shared libraries on non-x86
Linux platforms.  Since these libraries haven't become standard yet,
we'll just include them directly.

These sources are synchronized with XFree86 4.2.1