1 files changed, 11 insertions, 6 deletions

diff --git a/lisp/progmodes/cc-defs.el b/lisp/progmodes/cc-defs.el
index 9ea96358619..132019618c6 100644
--- a/lisp/progmodes/cc-defs.el
+++ b/lisp/progmodes/cc-defs.el
@@ -972,7 +972,11 @@ of any identifier.  Adorned regexps cannot be appended.  The language
 variable `c-nonsymbol-key' is used to make the adornment.  The
 optional MODE specifies the language to get it in.  The default is the
 current language (taken from `c-buffer-is-cc-mode')."
-  (setq list (delete-duplicates list :test 'string-equal))
+  (let (unique)
+    (dolist (elt list)
+      (unless (member elt unique)
+        (push elt unique)))
+    (setq list unique))
   (if list
       (let ((re (c-regexp-opt list)))
         ;; Add our own grouping parenthesis around re instead of
@@ -1326,11 +1330,12 @@ This macro does not do any hidden buffer changes."
         ;; are no file dependencies needed.
         (setq source-files (nreverse
                             ;; Reverse to get the right load order.
-                            (mapcan (lambda (elem)
-                                      (if (eq file (car elem))
-                                          nil ; Exclude our own file.
-                                        (list (car elem))))
-                                    (get sym 'source)))))
+                            (apply 'nconc
+                                   (mapcar (lambda (elem)
+                                             (if (eq file (car elem))
+                                                 nil ; Exclude our own file.
+                                               (list (car elem))))
+                                           (get sym 'source))))))
 
       ;; Spend some effort to make a compact call to
       ;; `c-get-lang-constant' since it will be compiled in.