biosuits, pents, and quads wear off are now gone. Sort of. They are
caused by places where two texture edges meet and there are little gaps
at the seams where nothing gets drawn. This is also why noclip screws w/
the screen if you walk outside of the map in the GL targets. We now draw
a backdrop whose color is set by r_clearcolor, ala software renderer.
No more compile warnings! A completely clean build on my system!
Wrapped all the unistd.h includes with #ifdef HAVE_UNISTD_H.
Seems like there is more, but that looks like it..
