[mutter] clutter/x11: Remove helper for checking XComposite presence

[Jonas Ådahl <jadahl src gnome org>]

commit 7e972685929ee5862fd66d9af1e14a86bb81c768
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Jul 9 21:02:36 2020 +0200

    clutter/x11: Remove helper for checking XComposite presence
    
    It's not used by anything.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1364

 clutter/clutter/x11/clutter-backend-x11.c | 43 -------------------------------
 clutter/clutter/x11/clutter-x11.h         |  3 ---
 2 files changed, 46 deletions(-)
---
diff --git a/clutter/clutter/x11/clutter-backend-x11.c b/clutter/clutter/x11/clutter-backend-x11.c
index e4bc3b8df3..4e970cdbe9 100644
--- a/clutter/clutter/x11/clutter-backend-x11.c
+++ b/clutter/clutter/x11/clutter-backend-x11.c
@@ -906,49 +906,6 @@ clutter_x11_remove_filter (ClutterX11FilterFunc func,
     }
 }
 
-/**
- * clutter_x11_has_composite_extension:
- *
- * Retrieves whether Clutter is running on an X11 server with the
- * XComposite extension
- *
- * Return value: %TRUE if the XComposite extension is available
- */
-gboolean
-clutter_x11_has_composite_extension (void)
-{
-  static gboolean have_composite = FALSE, done_check = FALSE;
-  int error = 0, event = 0;
-  Display *dpy;
-
-  if (done_check)
-    return have_composite;
-
-  if (!_clutter_context_is_initialized ())
-    {
-      g_critical ("X11 backend has not been initialised");
-      return FALSE;
-    }
-
-  dpy = clutter_x11_get_default_display();
-  if (dpy == NULL)
-    return FALSE;
-
-  if (XCompositeQueryExtension (dpy, &event, &error))
-    {
-      int major = 0, minor = 0;
-      if (XCompositeQueryVersion (dpy, &major, &minor))
-        {
-          if (major >= 0 && minor >= 3)
-            have_composite = TRUE;
-        }
-    }
-
-  done_check = TRUE;
-
-  return have_composite;
-}
-
 /**
  * clutter_x11_set_use_stereo_stage:
  * @use_stereo: %TRUE if the stereo stages should be used if possible.
diff --git a/clutter/clutter/x11/clutter-x11.h b/clutter/clutter/x11/clutter-x11.h
index a257360c7a..bdaf2cbd62 100644
--- a/clutter/clutter/x11/clutter-x11.h
+++ b/clutter/clutter/x11/clutter-x11.h
@@ -109,9 +109,6 @@ CLUTTER_EXPORT
 void         clutter_x11_remove_filter (ClutterX11FilterFunc func,
                                         gpointer             data);
 
-CLUTTER_EXPORT
-gboolean clutter_x11_has_composite_extension (void);
-
 CLUTTER_EXPORT
 void     clutter_x11_set_use_stereo_stage (gboolean use_stereo);
 CLUTTER_EXPORT