cmake GLESv2 examples

qt/qtbase src/gui/CMakeLists.txt :366 

find_package(GLESv2)

pyside/pyside-setup sources/pyside6/PySide6/QtGui/CMakeLists.txt :334 

find_package(GLESv2 REQUIRED)

qtproject/pyside-pyside-setup sources/pyside6/PySide6/QtGui/CMakeLists.txt :334 

find_package(GLESv2 REQUIRED)