=== modified file 'lisp/mail/sendmail.el'
--- lisp/mail/sendmail.el	2012-04-27 03:10:38 +0000
+++ lisp/mail/sendmail.el	2012-04-27 17:18:43 +0000
@@ -803,7 +803,7 @@
 	      t)))
     (do-auto-fill)))
 
-(defun mail-mode-fill-paragraph (arg)
+(defun mail-mode-fill-paragraph (&optional arg)
   ;; Do something special only if within the headers.
   (if (< (point) (mail-header-end))
       (let (beg end fieldname)