GLX/DRI2: handle swap event swap count wrapping

GLX/DRI2: handle swap event swap count wrapping

Create a new GLX drawable struct to track client related info, and add a
wrap counter to it drawable and track it as we receive events.  This
allows us to support the full 64 bits of the event structure we pass to
the client even though the server only gives us a 32 bit count.

Reviewed-by: Michel Dänzer <michel@daenzer.net>
Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>