In ES builds configure will now check for OpenGL ES 3.0 and 3.1
availability. This allows qopengl.h to include the correct header
and, by defining QT_OPENGL_ES_3 and QT_OPENGL_ES_3_1, the OpenGL
wrappers can provide support for MapBuffer, VAOs, etc. on GLES 3.0+
too. Right now this is not possible since the only standard way to
use an ES function specific to a given version is to use the function
directly. The extension mechanism (eglGetProcAddress and friends), that
is often used in desktop GL, is not available for such functions.
[ChangeLog][QtGui] QtGui's OpenGL headers are now automatically including
the highest available header (gl31.h, gl3.h or gl2.h) in OpenGL ES builds.
Task-number: QTBUG-38168
Change-Id: Ib857c58fe1696a9546fdd1aa143a9237e80325a5
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
