--- lisp/un-define.el.orig	Wed Mar  7 07:41:38 2001
+++ lisp/un-define.el	Thu May 16 22:15:03 2002
@@ -610,13 +610,21 @@
 
  (mapcar
   (lambda (x)
-    (mapcar
-     (lambda (y)
-       (mucs-define-coding-system
-	(nth 0 y) (nth 1 y) (nth 2 y)
-	(nth 3 y) (nth 4 y) (nth 5 y) (nth 6 y))
-       (coding-system-put (car y) 'alias-coding-systems (list (car x))))
-     (cdr x)))
+    (if (fboundp 'register-char-codings)
+	;; Mule 5, where we don't need the eol-type specified and
+	;; register-char-codings may be very slow for these coding
+	;; system definitions.
+	(let ((y (cadr x)))
+	  (mucs-define-coding-system
+	   (car x) (nth 1 y) (nth 2 y)
+	   (nth 3 y) (nth 4 y) (nth 5 y)))
+      (mapcar
+       (lambda (y)
+	 (mucs-define-coding-system
+	  (nth 0 y) (nth 1 y) (nth 2 y)
+	  (nth 3 y) (nth 4 y) (nth 5 y) (nth 6 y))
+	 (coding-system-put (car y) 'alias-coding-systems (list (car x))))
+       (cdr x))))
   `((utf-8
      (utf-8-unix
       ?u "UTF-8 coding system"
