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

warnings.

test/testpregap.c.in

@@ -1,7 +1,5 @@
 /*
-  $Id: testpregap.c.in,v 1.2 2008/06/10 00:45:09 pjcreath Exp $
-
-  Copyright (C) 2003, 2004, 2005 Rocky Bernstein <rocky@gnu.org>
+  Copyright (C) 2003, 2004, 2005, 2011 Rocky Bernstein <rocky@gnu.org>
   Copyright (C) 2008 Robert W. Fuller <hydrologiccycle@gmail.com>
   
   This program is free software: you can redistribute it and/or modify
@@ -23,6 +21,7 @@
 */
 #ifdef HAVE_CONFIG_H
 # include "config.h"
+# define __CDIO_CONFIG_H__ 1
 #endif
 #include <cdio/cdio.h>
 #include <cdio/cd_types.h>