Follow the usual pattern:
Add a config test and automatic include of GLES3/gl32.h if there
is a GLES 3.2 capable header+lib at build time.
Then, regardless of this being enabled, expose all new 3.2 API
functions in QOpenGLExtraFunctions and resolve them dynamically
at run time.
This way 3.2 functions will be available when deployed to a 3.2
capable system (or OpenGL 3/4.x with the functions in question
available) regardless of what was present in the sysroot at build
time.
Change-Id: Ia52551f3178591e1e56ceac8e45d89c6b13f4927
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
