WinRT: made OpenGL window-init work with latest round of ANGLE/WinRT updates Various constants in ANGLE/WinRT, both in MSOpenTech's ms-master branch, and in Google's branch, were changed again. This change makes SDL/WinRT work with them. To note, the ms-master branch (of ANGLE) was updated via this merge: https://github.com/MSOpenTech/angle/commit/bbd2eb0a9c453a941f2c7abacf616d5a66b6be92#diff-d1377fbe747de154e1bfcf7221d3de67