(is_address_field): New prototype.

 /* GNU Mailutils -- a suite of utilities for electronic mail
-   Copyright (C) 1999, 2000, 2001, 2002, 2005 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2000, 2001, 2002, 2005,
+   2006 Free Software Foundation, Inc.
 
    GNU Mailutils is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -370,6 +371,8 @@ void util_rfc2047_decode (char **value);
 
 void util_mark_read (mu_message_t msg);
 
+int is_address_field (const char *name);
+
 extern int ml_got_interrupt (void);
 extern void ml_clear_interrupt (void);
 extern void ml_readline_init (void);