Otherwise we may execute the callback before the value is actually
returned from RegisterWaitForSingleObject.

Gears Tactics shares a pointer to the returned handle with its callbacks
and calls UnregisterWait from there. This creates a race condition that
sometimes causes a double free.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47843Signed-off-by: Rémi Bernon <rbernon@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>