I grant that it is something of a hack, but using the CR_SYSTEM_GL_PATH environment variable is currently the only way that VirtualBox can be used with VirtualGL (see http://www.virtualgl.org/vgldoc/2_2evolving/#hd0013). As of 3.2.0, it appears that CR_NO_GL_SYSTEM_PATH has been defined in src/VBox/GuestHost/OpenGL/spu_loader/glloader.py, which prevents the CR_SYSTEM_GL_PATH environment variable from working and thus prevents VirtualBox from being used with VirtualGL.
If there is not a good reason for this functionality to be disabled, then please consider re-enabling it or working with us to find another solution for using VirtualBox with VirtualGL.
