Index: xemacs-21.5.29/lisp/files.el
===================================================================
--- xemacs-21.5.29.orig/lisp/files.el
+++ xemacs-21.5.29/lisp/files.el
@@ -166,7 +166,9 @@ This variable is relevant only if `backu
 Checks for files in the directory returned by `temp-directory' or specified
 by `small-temporary-file-directory'."
   (let ((temporary-file-directory (temp-directory)))
-    (not (or (let ((comp (compare-strings temporary-file-directory 0 nil
+    (not (or (null name)
+	     (string-match "^/tmp/" name)
+	     (let ((comp (compare-strings temporary-file-directory 0 nil
 					  name 0 nil)))
 	       ;; Directory is under temporary-file-directory.
 	       (and (not (eq comp t))