--- a/lisp/ChangeLog	Sun Jun 23 09:54:41 2002 +0000
+++ b/lisp/ChangeLog	Sun Jun 23 22:03:33 2002 +0000
@@ -1,3 +1,8 @@
+2002-06-22  Ville Skyttä  <ville.skytta@xemacs.org>
+
+	* subr.el (add-to-list): Sync with GNU Emacs 21.2, adding the
+	"&optional append" argument.
+
 2002-06-23  Stephen J. Turnbull  <stephen@xemacs.org>
 
 	* unicode.el (load-unicode-tables): Comment loading 8859-1.TXT.

--- a/lisp/subr.el	Sun Jun 23 09:54:41 2002 +0000
+++ b/lisp/subr.el	Sun Jun 23 22:03:33 2002 +0000
@@ -301,16 +301,24 @@
   (make-local-hook hook)
   (add-one-shot-hook hook function append t))
 
-(defun add-to-list (list-var element)
+(defun add-to-list (list-var element &optional append)
   "Add to the value of LIST-VAR the element ELEMENT if it isn't there yet.
 The test for presence of ELEMENT is done with `equal'.
+If ELEMENT is added, it is added at the beginning of the list,
+unless the optional argument APPEND is non-nil, in which case
+ELEMENT is added at the end.
+
 If you want to use `add-to-list' on a variable that is not defined
 until a certain package is loaded, you should put the call to `add-to-list'
 into a hook function that will be run only after loading the package.
 `eval-after-load' provides one way to do this.  In some cases
 other hooks, such as major mode hooks, can do the job."
-  (or (member element (symbol-value list-var))
-      (set list-var (cons element (symbol-value list-var)))))
+  (if (member element (symbol-value list-var))
+      (symbol-value list-var)
+    (set list-var
+         (if append
+             (append (symbol-value list-var) (list element))
+           (cons element (symbol-value list-var))))))
 
 ;; XEmacs additions
 ;; called by Fkill_buffer()