Use Debian's OpenGL.

--- evolver-2.26.orig/src/Makefile
+++ evolver-2.26/src/Makefile
@@ -58,9 +58,9 @@
 # Remove #'s from following 3 lines for LINUX with OpenGL GLUT graphics.
 # The graphics are on a second thread, so pthreads are needed.
 # NOTE: -DPTRHEADS is necessary with glutgraph.o.
-#CFLAGS= -DLINUX -DOOGL -DPTHREADS
-#GRAPH= glutgraph.o 
-#GRAPHLIB= -lGL -lGLU -lglut -lpthread
+CFLAGS= -DLINUX -DOOGL -DPTHREADS
+GRAPH= glutgraph.o 
+GRAPHLIB= -lGL -lGLU -lglut -lpthread
 # NOTE: It has been reported to me that RedHat 9 needs the following line
 # for GRAPHLIB, but earlier and later versions do okay with the GRAPHLIB
 # line just above.
