qfgl_ext.h:
Add protection against multiple includes of extensions from different files.
Add defs for GL_EXT_paletted_texture.
Change the #ifndef conditional for shared palettes to
GL_EXT_shared_texture_palette.
addition, removed support (for now) for SGIS and EXT multitexture. It
allowed me to enhance support for ARB multitexture, which is better anyway
(especially for Radeon, but that won't get special support yet until we
need a third texture pass).
Updated the Unix 8-bit GL code to be more like the Windows version, which
may work better. It still defaults off, because many drivers have bugs in
their handling of the shared texture palette extension.
interface. To detect an extension, call QFGL_ExtensionPresent(). To get
the address of an extension function, call QFGL_ExtensionAddress(). This
function uses the preferred method for finding a function, based on
whatever OS and windowing system you use.
