Some platforms have GLU libraries that don't behave properly in certain respects, and some Coin users have particular needs wrt. Coin's use of GLU. For these users, we (at Kongsberg Oil & Gas Technologies) have created a fork of SGI GLU 1.3 named SuperGLU that we have tweaked in certain ways. This library can be checked out into the Coin source code directory, which will be detected at configure-time and linked statically into Coin and used instead of the GLU libraries on the host system.