[metacity] use XSyncSetPriority()

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 9af4756999c32a2fccd3ab5ae110f1b30798f977
Author: Owen W. Taylor <otaylor fishsoup net>
Date:   Mon Nov 12 13:43:28 2012 -0500

    use XSyncSetPriority()
    
    Use XSyncSetPriority() to prioritize the compositor above applications
    for X server priority. In practice, this makes little difference because
    the Xorg "smart scheduler" will schedule in a single application for
    time slices that exceed the frame drawing time, but it's theoretically
    right and might make a difference if the X server scheduler is improved.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=685463

 src/core/display.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/src/core/display.c b/src/core/display.c
index ee0a02d..dee2ae0 100644
--- a/src/core/display.c
+++ b/src/core/display.c
@@ -449,7 +449,10 @@ meta_display_open (void)
         the_display->xsync_event_base = 0;
       }
     else
-      the_display->have_xsync = TRUE;
+      {
+        the_display->have_xsync = TRUE;
+        XSyncSetPriority (the_display->xdisplay, None, 10);
+      }
 
     meta_verbose ("Attempted to init Xsync, found version %d.%d error base %d event base %d\n",
                   major, minor,