Some people like to call this on bare Window XIDs and expect reasonable
results. I sure wish they wouldn't, but since they do, if we're given
a window without any glx decoration just fill in as much as we can. This
means you won't actually get an answer for GLX_FBCONFIG_ID and friends,
but there's not much to be done about that, and it matches what NVIDIA's
driver seems to do.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54080
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Adam Jackson <ajax@redhat.com>