(time-stamp-time-zone): Allow nil as alternative.

diff --git a/lisp/time-stamp.el b/lisp/time-stamp.el
index d8a279e00829b8d41b6676f131faddba4f358915..93c4f86af1d43b379452bce9220c59abac8a8cfa 100644 (file)
--- a/lisp/time-stamp.el
+++ b/lisp/time-stamp.el
@@ -113,7 +113,7 @@ If nil, no notification is given."
 (defcustom time-stamp-time-zone nil
   "If non-nil, a string naming the timezone to be used by \\[time-stamp].
 Format is the same as that used by the environment variable TZ on your system."
-  :type 'string
+  :type '(choice (const nil) string)
   :group 'time-stamp)