opengl/eglcontext: bail out early if we can't use complex shaders
Some old hardware is very limited in the amount of instructions it can support. In order to not have KWin fail to composite, reject using hardware acceleration in this case and fall back to llvmpipe or QPainter
(cherry picked from commit 5a0ecdba)
Co-authored-by: Xaver Hugl xaver.hugl@gmail.com