[mutter] xwayland: Add missing include

[Javier Jardón Cabezas <jjardon src gnome org>]

commit 6ea7fa99736373b1a4ca8d089c5f214650cd4e3c
Author: Javier Jardón <jjardon gnome org>
Date:   Sun Aug 23 11:38:27 2015 +0100

    xwayland: Add missing include
    
    https://bugzilla.gnome.org/show_bug.cgi?id=754621

 src/wayland/meta-xwayland-selection.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/wayland/meta-xwayland-selection.c b/src/wayland/meta-xwayland-selection.c
index 99a541d..b7f4830 100644
--- a/src/wayland/meta-xwayland-selection.c
+++ b/src/wayland/meta-xwayland-selection.c
@@ -33,6 +33,7 @@
 #include <gio/gunixinputstream.h>
 #include <gdk/gdkx.h>
 #include <X11/Xatom.h>
+#include <X11/extensions/Xfixes.h>
 #include <meta/errors.h>
 #include "meta-xwayland-private.h"
 #include "meta-xwayland-selection-private.h"