[quake3] SVN_1173 fails to compile

[Robert Isaac]

> Use a newer mingw32.  The latest build here has the proper OpenGL headers:
>
> http://www.libsdl.org/extras/win32/cross/
>
> An older version I had from there (from 2004) did not.
>

I am using a newer version with the OpenGL headers available from
here: http://www.libsdl.org/extras/win32/common/ which define
GL_ARB_multitexture.
Commenting out the #define seems to work, but that isn't a good fix..