The code we had for handling this with c11 cnd_t was gross. Let's use a
primitive that actually works.
Reviewed-by: Derek Foreman <derek.foreman@collabora.com>
Reviewed-by: Tatsuyuki Ishi <ishitatsuyuki@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29924>
This is mostly copy+paste (and a bit of re-typing) from ANV.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13427>
