Initialise gtkglext properly and force it not to use XmuLookupStandardColormap by setting an environment variable.
Initialise gtkglext properly and force it not to use XmuLookupStandardColormap by setting an environment variable.

git-svn-id: 4705079bc6b8aadf675e3696f5c015a6aa4916e3@4736 3c1deb5b-d424-0410-962d-aba41a686d42

hsorby/zinc,OpenCMISS/zinc,hsorby/zinc,OpenCMISS/zinc,hsorby/zinc,OpenCMISS/zinc,hsorby/zinc,OpenCMISS/zinc