Make sure config.h or the copy of that gets included only once to reduce duplicate include

warnings.

lib/udf/udf_fs.c

@@ -1,7 +1,5 @@
 /*
-  $Id: udf_fs.c,v 1.22 2008/04/18 16:02:10 karl Exp $
-
-  Copyright (C) 2005, 2006, 2008 Rocky Bernstein <rocky@gnu.org>
+  Copyright (C) 2005, 2006, 2008, 2011 Rocky Bernstein <rocky@gnu.org>
 
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -45,6 +43,7 @@
 
 #ifdef HAVE_CONFIG_H
 # include "config.h"
+# define __CDIO_CONFIG_H__ 1
 #endif
 
 #ifdef HAVE_STRING_H