(small-temporary-file-directory): Fix custom type.

diff --git a/lisp/files.el b/lisp/files.el
index 88f5b01ee8b658b96a1c32e8da3fc40de245a850..51eeaa73a717bf3adea1613129d3714bed066c20 100644 (file)
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -203,7 +203,7 @@ If non-nil, this directory is used instead of `temporary-file-directory'
 by programs that create small temporary files.  This is for systems that
 have fast storage with limited space, such as a RAM disk."
   :group 'files
-  :type 'directory)
+  :type '(choice (const nil) directory))
 
 ;; The system null device. (Should reference NULL_DEVICE from C.)
 (defvar null-device "/dev/null" "The system null device.")