Trouble compiling gnustep-back-0.8.3

[Tony Nelson]

I've been trying to get GNUstep up and running. The following works fine:
gnustep-make
./configure --prefix=(my homedir)/GNUstep; make; make install

gnustep-base
./configure; make; make install

gnustep-gui
./configure; make; make install

but when I ./configure; make the back source, I get the following error:

...
Making all for subproject x11...
 Compiling file XGServer.m ...
In file included from XGServer.m:51:
../../Headers/x11/XGOpenGL.h:43: parse error before `GLXWindow'
../../Headers/x11/XGOpenGL.h:52: parse error before `GLXFBConfig'
make[3]: *** [shared_obj/ix86/linux-gnu/gnu-gnu-gnu/XGServer.o] Error 1
make[2]: *** [x11.all.subproject.variables] Error 2
make[2]: Leaving directory 
`/nh/toaster/u/tenelson/bin/gnustep-back-0.8.3/Source/x11'
make[1]: *** [libgnustep-back.all.bundle.variables] Error 2
make[1]: Leaving directory 
`/nh/toaster/u/tenelson/bin/gnustep-back-0.8.3/Source'
make: *** [internal-all] Error 2
...

I have also installed gnustep-objc (before gnustep-make). Any ideas what could 
be happening?
I'm using Redhat 7.2 and aim to install all of the GNUstep stuff into my home 
directory.
thanks.