FindOpenGL: Switch legacy GL interfaces to link GLVND

!782 (merged) added support for GLVND but #17437 (closed) identified that using it by default breaks compatibility so !1466 (merged) switched the default back to the legacy GL library. A CMake Policy will be needed to migrate to GLVND in a compatible way.

Edited Nov 09, 2017 by Brad King

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information