x11/group: Make various functions private

Nothing uses them and they are X11 only

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3776>

src/meta/group.h

@@ -21,9 +21,7 @@
 
 #pragma once
 
-#ifdef HAVE_X11_CLIENT
 #include <X11/Xlib.h>
-#endif
 #include <glib.h>
 
 #include "meta/common.h"
@@ -36,23 +34,3 @@ MetaGroup * meta_window_x11_get_group (MetaWindow *window);
 
 META_EXPORT
 GSList*    meta_group_list_windows     (MetaGroup *group);
-
-#ifdef HAVE_X11_CLIENT
-/* note, can return NULL */
-META_EXPORT
-MetaGroup *meta_x11_display_lookup_group (MetaX11Display *x11_display,
-                                          Window          group_leader);
-
-META_EXPORT
-void       meta_group_update_layers    (MetaGroup *group);
-
-META_EXPORT
-const char* meta_group_get_startup_id  (MetaGroup *group);
-
-META_EXPORT
-int        meta_group_get_size         (MetaGroup *group);
-
-META_EXPORT
-gboolean meta_group_property_notify   (MetaGroup  *group,
-                                       XEvent     *event);
-#endif

src/x11/group-private.h

@@ -39,3 +39,14 @@ MetaGroup * meta_group_new (MetaX11Display *x11_display,
                             Window          group_leader);
 
 void meta_group_unref (MetaGroup *group);
+
+/* note, can return NULL */
+MetaGroup * meta_x11_display_lookup_group (MetaX11Display *x11_display,
+                                           Window          group_leader);
+
+void meta_group_update_layers (MetaGroup *group);
+
+const char* meta_group_get_startup_id (MetaGroup *group);
+
+gboolean meta_group_property_notify (MetaGroup  *group,
+                                     XEvent     *event);

src/x11/group.c

@@ -220,12 +220,4 @@ meta_group_property_notify (MetaGroup  *group,
 
 }
 
-int
-meta_group_get_size (MetaGroup *group)
-{
-  if (!group)
-    return 0;
-
-  return group->refcount;
-}