common_quakedef.h (and thus all files)
This solves a build break when the OpenGL includes are not in /usr/include,
since the OpenGL include path is only used when compiling files that use
OpenGL.
like adding a gratuitious feature, GL target users can crosshair 3 for a
completely new crosshair and higher resolution crosshair (oooh!) Software
renderer doesn't have it because...well look at Draw_Crosshair() in
draw.c, it's truly a nightmare! You have to plot each pixel individually,
makes you feel like you're coding in Applesoft BASIC. If you want it,
figure out how to do it sanely.
