bug#583: Use XDG basedir spec for configuration files?

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Date: Wed, 28 Aug 2019 12:11:21 -0400
> Cc: ferkiwi+a@gmail.com, eggert@cs.ucla.edu
> 
> It's great to finally see some progress in this area, but IIUC this is
> still not really following the XDG spec. For example, I think a proper
> solution would see user elpa packages stored undo XDG_DATA_HOME, etc.

Yes, because we don't set user-emacs-directory from XDG_DATA_HOME.  We
only load the init files from there.