cmake OpenGLES2 examples

o2-engine/o2 CMakeLists.txt :182 

find_package(OpenGLES2 REQUIRED)

qwertzui11/voxelTerrain cmake/Modules/FindOGRE.cmake :268 

find_package(OpenGLES2 QUIET)

liballeg/allegro5 CMakeLists.txt :645 

find_package(OpenGLES2)