autoload.el fix for bug#10049

* lisp/emacs-lisp/autoload.el (autoload-generate-file-autoloads):
Ignore buffer-local generated-autoload-file if it is the same
as the global value.

lisp/ChangeLog

+2011-11-17  Glenn Morris  <rgm@gnu.org>
+
+	* emacs-lisp/autoload.el (autoload-generate-file-autoloads):
+	Ignore buffer-local generated-autoload-file if it is the same
+	as the global value.  (Bug#10049)
+
 2011-11-17  Juanma Barranquero  <lekktu@gmail.com>
 
 	* textmodes/reftex-toc.el (reftex-toc-return-marker, reftex-toc-help)

lisp/emacs-lisp/autoload.el

@@ -514,6 +514,13 @@ Return non-nil if and only if FILE adds no autoloads to OUTFILE
             (let ((secondary-autoloads-file-buf
                    (if (local-variable-p 'generated-autoload-file)
                        (current-buffer))))
+	      ;; Ignore a buffer-local setting if it points to the
+	      ;; global value.  Otherwise we end up writing a mix of md5s
+	      ;; and time-stamps to the global file.  (Bug#10049)
+	      (and secondary-autoloads-file-buf
+		   outfile
+		   (not otherbuf)
+		   (setq secondary-autoloads-file-buf nil))
               (with-current-buffer (marker-buffer output-start)
                 (save-excursion
                   ;; Insert the section-header line which lists the file name