(auto-save-list-file-prefix): Set default to

`~/.emacs.d/auto-save-list/.saves-' for systems other than MS-DOS.

lisp/startup.el

@@ -317,13 +317,16 @@ after your init file is read, in case it sets `mail-host-address'."
   :group 'mail)
 
 (defcustom auto-save-list-file-prefix
-  (if (eq system-type 'ms-dos)
-      "~/_s"  ; MS-DOS cannot have initial dot, and allows only 8.3 names
-    "~/.saves-")
+  (cond ((eq system-type 'ms-dos)
+	 ;; MS-DOS cannot have initial dot, and allows only 8.3 names
+	 "~/_s")
+	(t
+	 "~/.emacs.d/auto-save-list/.saves-"))
   "Prefix for generating `auto-save-list-file-name'.
 This is used after reading your `.emacs' file to initialize
 `auto-save-list-file-name', by appending Emacs's pid and the system name,
 if you have not already set `auto-save-list-file-name' yourself.
+Directories in the prefix will be created if necessary.
 Set this to nil if you want to prevent `auto-save-list-file-name'
 from being initialized."
   :type '(choice (const :tag "Don't record a session's auto save list" nil)