Allow compiling against Qt configured with -no-opengl
This is no longer possible since 66c5bb0e.
Guard those newly-added checks with #if QT_CONFIG(opengl)
to restore
the ability to build without openGL.
This is no longer possible since 66c5bb0e.
Guard those newly-added checks with #if QT_CONFIG(opengl)
to restore
the ability to build without openGL.