As the surface->backend will be NULL in such an error surface, and we
may be legitimately doing boundary checks to reject the error surface.
The alternative would be to set an explicit error surface backend.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54664
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
The check for standalone headers requires that the
cairo-image-surface-inline.h include the cairo-surface-private.h
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>