Allow --disable-opengl-glib, also check for all three headers (GL/GLU/GLUT) before building.
Allow --disable-opengl-glib, also check for all three headers (GL/GLU/GLUT) before building.

svn path=/trunk/; revision=814

danilocesar/seed,danilocesar/seed,danilocesar/seed,danilocesar/seed,danilocesar/seed