customize eshell-alias loading

[Kevin Ryde]

An example of the customize autoloading problems I mentioned that I
thought I'd been hitting is em-alias.el.

For instance with the emacs cvs on a recent i386 debian, if you fire
up emacs -q -no-site-file in the usual way and then

        M-x customize-group eshell-alias

you get just

        Eshell Aliases File

but if instead you fire up and do

        M-x eshell
        M-x customize-group eshell-alias

you get more things to customize

        Eshell Aliases File
        Eshell Bad Command Tolerance
        Eshell Alias Load Hook

I'm guessing this is because em-alias.el (the :load for the
eshell-alias group) doesn't like to be loaded without the main eshell
loaded,

        (require 'em-alias)

gives

        Debugger entered--Lisp error: (void-variable eshell-directory-name)
          (concat eshell-directory-name "alias")
          eval((concat eshell-directory-name "alias"))
          custom-initialize-reset(eshell-aliases-file (concat 
eshell-directory-name "al$
          custom-declare-variable(eshell-aliases-file (concat 
eshell-directory-name "al$
          require(em-alias)
          eval((require (quote em-alias)))
          eval-expression((require (quote em-alias)) nil)
          call-interactively(eval-expression)

(I'm not trying to pick on eshell here, it was just one I'd struck.)

Should an M-x customize-group to a particular group work, without
going through its parents or whatever?  Perhaps the relevant variables
or groups need more in their autoload lists.