Add fence sync driver interface

-Add fence sync objects

-Add fence sync devPrivates

-Add a X sync module screen private

-Add wrappable functions to create and destroy
 fence sync objects

-Give fence sync objects wrappable functions to
 trigger, test, and reset their 'triggered' value.

-Give fence sync objects wrappable functions to
 notify driver when adding/removing triggers to/
 from the sync object.

Signed-off-by: James Jones <jajones@nvidia.com>
Reviewed-by: Keith Packard <keithp@keithp.com>

dix/privates.c

@@ -447,6 +447,7 @@ static const char *key_names[PRIVATE_LAST] = {
     [PRIVATE_GLYPH] = "GLYPH",
     [PRIVATE_GLYPHSET] = "GLYPHSET",
     [PRIVATE_PICTURE] = "PICTURE",
+    [PRIVATE_SYNC_FENCE] = "SYNC_FENCE",
 };
 
 void