YaGL/VIGS: GLESv3 workarounds for Mac OS X 10.7
Mac OS X 10.7 supports OpenGL 3.2, however, it doesn't have
all the necessary functions implemented in order to implement
GLESv3 on target. This workaround checks for some mandatory
functions and if at least one of them is not present - we revert
back to OpenGL 2.1. A nicer fix would be checking for OpenGL
functions globally, not in CGL backend, this is a TODO
Change-Id: I9c0acce3220af9ed7276a8586fa18b97d8223079
Signed-off-by: Stanislav Vorobiov <s.vorobiov@samsung.com>