cleanup: Remove not used X11 includes

Also add ones where they are actually used

Helps https://gitlab.gnome.org/GNOME/mutter/-/issues/2272

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3603>

src/backends/meta-idle-monitor.c

@@ -29,8 +29,6 @@
 #include "config.h"
 
 #include <string.h>
-#include <X11/Xlib.h>
-#include <X11/extensions/sync.h>
 
 #include "backends/gsm-inhibitor-flag.h"
 #include "backends/meta-backend-private.h"

src/backends/x11/meta-backend-x11.h

@@ -24,6 +24,8 @@
 
 #include <stdint.h>
 #include <X11/Xlib.h>
+#include <X11/extensions/XInput.h>
+#include <X11/extensions/XInput2.h>
 
 #include "backends/meta-backend-private.h"
 #include "backends/x11/meta-backend-x11-types.h"

src/compositor/compositor-private.h

@@ -2,8 +2,6 @@
 
 #pragma once
 
-#include <X11/extensions/Xfixes.h>
-
 #include "clutter/clutter-mutter.h"
 #include "clutter/clutter.h"
 #include "compositor/meta-compositor-view.h"

src/core/window-private.h

@@ -31,8 +31,6 @@
 
 #pragma once
 
-#include <X11/Xutil.h>
-
 #include "backends/meta-logical-monitor.h"
 #include "clutter/clutter.h"
 #include "core/stack.h"

src/meta/common.h

@@ -24,9 +24,6 @@
 
 #pragma once
 
-#include <X11/Xlib.h>
-#include <X11/extensions/XInput.h>
-#include <X11/extensions/XInput2.h>
 #include <glib.h>
 
 #include "clutter/clutter.h"

src/meta/display.h

@@ -20,7 +20,6 @@
 #pragma once
 
 #include <glib-object.h>
-#include <X11/Xlib.h>
 
 #include "meta/types.h"
 #include "meta/prefs.h"

src/meta/meta-shaped-texture.h

@@ -23,8 +23,6 @@
 
 #pragma once
 
-#include <X11/Xlib.h>
-
 #include "clutter/clutter.h"
 #include "meta/common.h"
 #include "meta/meta-multi-texture.h"

src/meta/meta-x11-display.h

@@ -21,6 +21,7 @@
 
 #include <glib-object.h>
 #include <X11/Xlib.h>
+#include <X11/extensions/Xfixes.h>
 
 #include "meta/common.h"
 #include "meta/prefs.h"

src/meta/window.h

@@ -20,7 +20,6 @@
 #pragma once
 
 #include <glib-object.h>
-#include <X11/Xlib.h>
 
 #include "meta/boxes.h"
 #include "meta/types.h"

src/x11/group-private.h

@@ -23,6 +23,8 @@
 
 #include "meta/group.h"
 
+#include <X11/Xlib.h>
+
 struct _MetaGroup
 {
   int refcount;

src/x11/window-props.h

@@ -29,6 +29,8 @@
 
 #pragma once
 
+#include <X11/Xutil.h>
+
 #include "core/window-private.h"
 
 /**