I used osgSetGLExtensionsFuncPtr to remove the symbols. I don't know how to test this path, but it did remove the symbols from libosgViewer.so. I have also not been able yet to see if that was sufficient for our customer.
I did this by looking at other cases, and I tried to follow some of the same practices in PixelBufferX11, like using _useSGIX in a similar way to the previous _useGLX1_3."
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/branches/OpenSceneGraph-3.4@15042 16af8721-9629-0410-8352-f15c8da7e697