Make lm-verify footer checking more strict

* lisp/emacs-lisp/lisp-mnt.el (lm-verify): Make file footer regexp
more strict to match requirement in old versions of package.el (now
only a warning).

lisp/emacs-lisp/lisp-mnt.el

@@ -519,6 +519,7 @@ says display \"OK\" in temp buffer for files that have no problems.
 Optional argument VERBOSE specifies verbosity level.
 Optional argument NON-FSF-OK if non-nil means a non-FSF
 copyright notice is allowed."
+  ;; FIXME: Make obsolete in favor of checkdoc?
   (interactive (list nil nil t))
   (let* ((ret (and verbose "Ok"))
 	 name)
@@ -562,9 +563,8 @@ copyright notice is allowed."
 		  (goto-char (point-max))
 		  (not
 		   (re-search-backward
-		    (concat "^;;;[ \t]+" name "[ \t]+ends here[ \t]*$"
-			    "\\|^;;;[ \t]+ End of file[ \t]+" name)
-		    nil t)))
+                    (rx bol ";;; " (eval name) " ends here")
+                    nil t)))
 		"Can't find the footer line")
 	       ((not (and (lm-copyright-mark) (lm-crack-copyright)))
 		"Can't find a valid copyright notice")