Putting all backup (tilde) files in one directory using xemacs 21.4p6

["Kelly Jones" <kelly.terry.jones@gmail.com>]

Using xemacs 21.4p6, how do I put all backup (tilde) files into a
single directory, instead of having them saved to the same directory
as the original file?

I tried several variations of:

(require 'saveconf)
(require 'uniquify)
(require 'auto-save)
(setq backup-directory-alist '(("." . "/home/user/emacs-backups")))

to no avail (I replaced 'user' with my username and confirmed that
emacs-backups existed and was writable by me).

I then wiped out all the tilde files, restarted xemacs, ran the LISP
code above, but the tilde files still show up in the same directory as
the original.

Doing "describe-variable" for "backup-directory-alist" is unhelpful,
so I wonder if I need to "require" something else to make this work?

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