The fedora SRPMs now have patches to fix this. you should be able to just use those.
http://cvs.fedoraproject.org/viewvc/F-13/mathgl/mathgl-mglview-ldflags.patch?revision=1.1&view=markup
http://cvs.fedoraproject.org/viewvc/F-13/mathgl/mathgl-examples-ldflags.patch?revision=1.1&view=markup