They've been implemented for a while, but we never advertised them. All we
need to do is set the GLX_PBUFFER_BIT in the drawable type fbconfig
field when we're using DRI2.
https://bugs.freedesktop.org/show_bug.cgi?id=26581
Signed-off-by: Kristian Høgsberg <krh@bitplanet.net>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>