[CMake] FindOpenGL.cmake proposed patch

[Bill Hoffman]

James Bigler wrote:
> Has something changed with respect to how the NVIDIA drivers were
> installed?  I thought they overwrote the files in /usr/include/GL
> while moving the old ones out?  I've never seen a case where gl.h and
> glu.h were in different places.  If you have examples of this, that
> would be great.
> 

I checked with some GPU programming folks here at Kitware, and:

> On my debian, the OS reports that glu.h belongs to package
> libglu1-mesa-dev and gl.h belongs to package mesa-common-dev.
> 
> $ dpkg -S /usr/include/GL/glu.h
> 
> libglu1-mesa-dev: /usr/include/GL/glu.h
> 
> $ dpkg -S /usr/include/GL/gl.h
> 
> mesa-common-dev: /usr/include/GL/gl.h


-Bill