[Bug: 21.5-b29] Xemacs ignores custom.el

[Stephen J. Turnbull]

Jeff Sparkes writes:

 > Odd, from my xemacs -q *scratch-buffer* on Ubuntu, with a build no
 > more than two weeks old:
 > 
 >  emacs-version
 > "21.5  (beta29) \"garbanzo\" 70b15ac66ee5+ XEmacs Lucid"
 > custom-file
 > nil

You can't test it with -q.  custom-file is computed dynamically using
`make-custom-file-name' (in lisp/cus-file.el) in `load-user-init-file'
(in lisp/startup.el).  If you do -q, all that code is bypassed until
you load the init files.

 > I've had it set to "~/.xemacs/custom.el" for years.  I think that should be
 > the default

It *is* the default.  See lisp/cus-file.el.

 > so that customize doesn't mess with my ~/.xemacs/init.el

It shouldn't.  If custom-file is nil, attempts to save customizations
fail with "Wrong type argument: stringp, nil".  (Quick reading of the
code, lightly tested, too.)