glamor core profile support

[Dave Airlie]

This series implements support for glamor in ephyr/EGL/Xwayland
to use GL core profile when it can.

This required 4 main changes:
a) stop using client ptrs everywhere, I found 3 places left,
gradient, picture and xv where we use these.
b) start using VAOs
c) use GL_RED instead of GL_ALPHA
d) stop using GL_QUADS.

These patches are also in my glamor-core-profile branch.

Dave.