Call the standard functions directly in GLES 3.0+ builds.
The catch here, just like with the mapBuffer changes, is that we could,
in theory, dynamically load a GLES3 implementation on the !QT_OPENGL_ES_3
path too. However this is limited to Windows currently and we don't have
a full GLES3 stack there (yet), and even when we do get it, the ANGLE
extensions for blit and multisampling will still work. Therefore this
isn't really an issue for now.
Task-number: QTBUG-38168
Task-number: QTBUG-39187
Change-Id: I343a737218c9fe438ee1603b37e93f0400d952a5
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
33e9aeca7f