(rmail-movemail-program): Fix customize type.

diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
index 6e609a6dfc393fa214471595c29a87f982862045..e0e5237133b0489e2ef14bac8bb5a5ff34b29826 100644 (file)
--- a/lisp/mail/rmail.el
+++ b/lisp/mail/rmail.el
@@ -87,7 +87,7 @@
 (defcustom rmail-movemail-program nil
   "If non-nil, name of program for fetching new mail."
   :group 'rmail-retrieve
-  :type 'string)
+  :type '(choice (const nil) string))
 
 (defcustom rmail-pop-password nil
   "*Password to use when reading mail from a POP server, if required."