Some drivers dont support const array
Add a function to query supported glsl ver
Do not build shadow shader without gs support.
Merge commit 'f3e2da881a4d394c4ca902548e788f5b4c0bdd81'

* commit 'f3e2da881a4d394c4ca902548e788f5b4c0bdd81':
  Do not build shadow shader without gs support.
  Add a function to query supported glsl ver
  Some drivers dont support const array