Fix empty macro expansions.  Xlib.h preprocessed correctly now.
Fix empty macro expansions.  Xlib.h preprocessed correctly now.

mammadori/pyglet,adamlwgriffiths/Pyglet,mammadori/pyglet,oktayacikalin/pyglet,seeminglee/pyglet64,adamlwgriffiths/Pyglet,niklaskorz/pyglet,niklaskorz/pyglet,oktayacikalin/pyglet,theblacklion/pyglet,mammadori/pyglet,theblacklion/pyglet,seeminglee/pyglet64,mammadori/pyglet,theblacklion/pyglet,adamlwgriffiths/Pyglet,oktayacikalin/pyglet,oktayacikalin/pyglet,oktayacikalin/pyglet,theblacklion/pyglet,theblacklion/pyglet,adamlwgriffiths/Pyglet,seeminglee/pyglet64,niklaskorz/pyglet,niklaskorz/pyglet