From 233f3fb8deca3a616d46ea217834221d3dc6b2e1 Mon Sep 17 00:00:00 2001
From: "Richard M. Stallman" <rms@gnu.org>
Date: Tue, 9 Sep 1997 02:56:56 +0000
Subject: [PATCH] (shell-chdrive-regexp): Likewise.

---
 lisp/shell.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lisp/shell.el b/lisp/shell.el
index c28f1649eb6..1b8c9da313a 100644
--- a/lisp/shell.el
+++ b/lisp/shell.el
@@ -235,7 +235,8 @@ This mirrors the optional behavior of tcsh."
       "[]a-zA-Z^_`\\[\\\\]:"
     nil)
   "*If non-nil, is regexp used to track drive changes."
-  :type 'regexp
+  :type '(choice regexp
+		 (const nil))
   :group 'shell-directories)
 
 (defcustom explicit-shell-file-name nil
-- 
2.39.2