(font-lock-set-defaults): Do nothing if font-lock-keywords is already set.

diff --git a/lisp/font-lock.el b/lisp/font-lock.el
index 5081874ca904af9bbc33c6d1c041ff13d4d24be8..9af71b86d898e04c173c853666c915bea112a266 100644 (file)
--- a/lisp/font-lock.el
+++ b/lisp/font-lock.el
@@ -409,16 +409,17 @@ This can take a while for large buffers."
 
 (defun font-lock-set-defaults ()
   "Set `font-lock-keywords' to something appropriate for this mode."
-  (setq font-lock-keywords
-       (cond ((eq major-mode 'lisp-mode)       lisp-font-lock-keywords)
-             ((eq major-mode 'emacs-lisp-mode) lisp-font-lock-keywords)
-             ((eq major-mode 'c-mode)          c-font-lock-keywords)
-             ((eq major-mode 'c++-c-mode)      c-font-lock-keywords)
-             ((eq major-mode 'c++-mode)        c++-font-lock-keywords)
-             ((eq major-mode 'perl-mode)       perl-font-lock-keywords)
-             ((eq major-mode 'tex-mode)        tex-font-lock-keywords)
-             ((eq major-mode 'texinfo-mode)    texi-font-lock-keywords)
-             (t nil))))
+  (if (not font-lock-keywords)         ; if not already set.
+      (setq font-lock-keywords
+           (cond ((eq major-mode 'lisp-mode)       lisp-font-lock-keywords)
+                 ((eq major-mode 'emacs-lisp-mode) lisp-font-lock-keywords)
+                 ((eq major-mode 'c-mode)          c-font-lock-keywords)
+                 ((eq major-mode 'c++-c-mode)      c-font-lock-keywords)
+                 ((eq major-mode 'c++-mode)        c++-font-lock-keywords)
+                 ((eq major-mode 'perl-mode)       perl-font-lock-keywords)
+                 ((eq major-mode 'tex-mode)        tex-font-lock-keywords)
+                 ((eq major-mode 'texinfo-mode)    texi-font-lock-keywords)
+                 (t nil))))
 
 (defconst lisp-font-lock-keywords-1
  '(;;