Remove `remove-duplicates', since `delete-dups' is sufficient.

lisp/ChangeLog

+2011-07-12  Lars Magne Ingebrigtsen  <larsi@gnus.org>
+
+	* subr.el (remove-duplicates): Remove; `delete-dups' is sufficient.
+
+	* dired-x.el (dired-guess-default): Use `delete-dups'.
+
 2011-07-12  Chong Yidong  <cyd@stupidchicken.com>
 
 	* dired.el (dired-mark-prompt):

lisp/dired-x.el

@@ -1103,7 +1103,7 @@ See `dired-guess-shell-alist-user'."
     ;; Return commands or nil if flist is still non-nil.
     ;; Evaluate the commands in order that any logical testing will be done.
     (if (cdr cmds)
-	(remove-duplicates (mapcar #'eval cmds))
+	(delete-dups (mapcar #'eval cmds))
       (eval (car cmds)))))		; single command
 
 (defun dired-guess-shell-command (prompt files)

lisp/subr.el

@@ -173,7 +173,7 @@ value of last one, or nil if there are none.
     (progn
   ;; If we reload subr.el after having loaded CL, be careful not to
   ;; overwrite CL's extended definition of `dolist', `dotimes',
-  ;; `declare', `push', `pop' and `remove-duplicates'.
+  ;; `declare', `push' and `pop'.
 
 (defmacro dolist (spec &rest body)
   "Loop over a list.
@@ -250,15 +250,6 @@ the return value (nil if RESULT is omitted).
 Treated as a declaration when used at the right place in a
 `defmacro' form.  \(See Info anchor `(elisp)Definition of declare'.)"
   nil)
-
-(defun remove-duplicates (list)
-  "Return a copy of LIST with all duplicate elements removed."
-  (let ((result nil))
-    (while list
-      (unless (member (car list) result)
-	(push (car list) result))
-      (pop list))
-    (nreverse result)))
 ))
 
 (defmacro ignore-errors (&rest body)