[mutter] Fix srcdir != builddir

[Giovanni Campagna <gcampagna src gnome org>]

commit d99c0ad3846a6a2283ddd8df1cd783689516d472
Author: Giovanni Campagna <gcampagn redhat com>
Date:   Fri Aug 23 16:31:29 2013 +0200

    Fix srcdir != builddir

 src/Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index 1af64d2..5120482 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -357,4 +357,4 @@ $(dbus_idle_built_sources) : Makefile.am idle-monitor.xml
                --c-namespace MetaDBus                                                  \
                --generate-c-code meta-dbus-idle-monitor                                \
                --c-generate-object-manager                                             \
-               idle-monitor.xml
+               $(srcdir)/idle-monitor.xml