Info-dir-remove-duplicates is slow

[Helmut Eller <e9626484@stud3.tuwien.ac.at>]

With the current CVS Emacs, info is quite slow.  Calling (info) takes
about 1.7 seconds here.  I've already set
Info-fontify-maximum-menu-size to 30000 and so fontification is
disabled.  (With fontification it takes 2.4 seconds.)

With the patch below it takes about only 0.3 seconds.  

The modification is quite small: it replaces the expensive call to
member-ignore-case with a call to member and only keeps downcased
strings around.

Helmut.

--- info.el	07 Aug 2005 16:06:08 +0200	1.438
+++ info.el	07 Aug 2005 23:51:10 +0200	
@@ -1152,17 +1152,17 @@ (defun Info-dir-remove-duplicates ()
 	      (delete-region (1- (point)) (point))))
 
 	  ;; Now remove duplicate entries under the same heading.
-	  (let ((seen nil)
+	  (let ((seen '())
 		(limit (point)))
 	    (goto-char start)
 	    (while (re-search-forward "^* \\([^:\n]+:\\(:\\|[^.\n]+\\).\\)"
 				      limit 'move)
-	      (let ((x (match-string 1)))
-	  	(if (member-ignore-case x seen)
+	      (let ((key (downcase (match-string 1))))
+	  	(if (member key seen)
 	  	    (delete-region (match-beginning 0)
 	  			   (progn (re-search-forward "^[^ \t]" nil t)
 	  				  (match-beginning 0)))
-	  	  (push x seen))))))))))
+	  	  (push key seen))))))))))
 
 ;; Note that on entry to this function the current-buffer must be the
 ;; *info* buffer; not the info tags buffer.