[metacity] theme: fix warning

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 3a3c47e3124fed711605deb15fbad2243f277e03
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Thu Feb 19 18:49:28 2015 +0200

    theme: fix warning

 src/ui/theme.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/ui/theme.c b/src/ui/theme.c
index b4ea955..3ee5d04 100644
--- a/src/ui/theme.c
+++ b/src/ui/theme.c
@@ -52,6 +52,7 @@
 
 #include <config.h>
 #include "frames.h" /* for META_TYPE_FRAMES */
+#include "prefs.h"
 #include "theme.h"
 #include "theme-parser.h"
 #include "util.h"