Index: startxfce4.in
===================================================================
--- startxfce4.in	(revision 20857)
+++ startxfce4.in	(working copy)
@@ -26,6 +26,14 @@
   BASEDIR=$XDG_CONFIG_HOME/xfce4
 fi
 
+if test x"$XDG_DATA_DIRS" = x""
+then
+  XDG_DATA_DIRS="@datadir@"
+else
+  XDG_DATA_DIRS="$XDG_DATA_DIRS:@datadir@"
+fi
+export XDG_DATA_DIRS
+
 if test x"$DISPLAY" = x""
 then
   echo "$0: Starting X server"