XRender defines this, GL really doesn't like it.
kwin 4.x and qt 4.x seem to make this happen for the
gradient in the titlebar, and on radeonsi/r600 hw
this draws all kinds of wrong.
v2: bump this up a level, and check it earlier.
(I assume the XXXX was for this case.)
v3: add same code to largepixmap paths (Keith)
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Jasper St. Pierre <jstpierre@mecheye.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>