Sorting: Make priority sorting work under XEmacs

The XEmacs default sorting function does not work correctly with
characters, probably because characters in XEmacs are not integers.

lisp/ChangeLog

@@ -1,5 +1,8 @@
 2009-04-30  Carsten Dominik  <carsten.dominik@gmail.com>
 
+	* org.el (org-sort-entries-or-items): Explicit sorting function
+	for priorities, needed for XEmacs compatibility.
+
 	* org-remember.el (org-remember-apply-template): Improve auto-save
 	behavior.
 

lisp/org.el

@@ -6248,6 +6248,7 @@ WITH-CASE, the sorting considers case as well."
           ((= dcst ?a) 'string<)
           ((= dcst ?t) 'time-less-p)
           ((= dcst ?f) compare-func)
+          ((= dcst ?p) '<)
           (t nil)))))
     (message "Sorting entries...done")))