(rmail-mbox-from): Move to mail-utils.

Update callers for name change.

lisp/mail/rmailout.el

@@ -308,20 +308,7 @@ Replaces the From line with a \"Mail-from\" header.  Adds \"Date\" and
 		    "From: \\1\n"))
 		t)))))))
 
-;; Note this is duplicated in unrmail.el.
-(defun rmail-mbox-from ()
-  "Return a \"From \" line for the current message.
-The buffer should be narrowed to just the header."
-  (let ((from (or (mail-fetch-field "from")
-		  (mail-fetch-field "really-from")
-		  (mail-fetch-field "sender")
-		  "unknown"))
-	(date (mail-fetch-field "date")))
-    (format "From %s %s\n" (mail-strip-quoted-names from)
-	    (or (and date
-		     (ignore-errors
-		      (current-time-string (date-to-time date))))
-		(current-time-string)))))
+(autoload 'mail-mbox-from "mail-utils")
 
 (defun rmail-output-as-mbox (file-name nomsg &optional as-seen)
   "Convert the current buffer's text to mbox and output to FILE-NAME.
@@ -344,7 +331,7 @@ AS-SEEN is non-nil if we are copying the message \"as seen\"."
        "Mail-From\\|MIME-Version\\|Content-type"))
     (goto-char (point-min))
     (or (looking-at "From ")
-	(insert (rmail-mbox-from)))
+	(insert (mail-mbox-from)))
     (widen)
     ;; Make sure message ends with blank line.
     (goto-char (point-max))
@@ -451,7 +438,7 @@ from a non-Rmail buffer.  In this case, COUNT is ignored."
 		;; rmail-convert-to-babyl-format errors if no From line,
 		;; whereas rmail-output-as-mbox inserts one.
 		(or (looking-at "From ")
-		    (insert (rmail-mbox-from)))
+		    (insert (mail-mbox-from)))
 		(rmail-output-as-babyl file-name noattribute))
 	    (rmail-output-as-mbox file-name noattribute)))
       ;; Called from an Rmail buffer.