bug#22613: 25.1.50; dired-aux missing require 'cl-lib

[Eli Zaretskii]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Cc: Tino Calancha <f92capac@gmail.com>,  22613@debbugs.gnu.org
> Date: Sat, 13 Feb 2016 15:32:45 +0100
> 
> > cl-mapcan is an autoloaded function, so requiring cl-lib is not the
> > right solution, IMO.  Some other factor is at work here.
> 
> Yes, hmm, I also saw that once: cl-lib autoloads were not loaded
> (i.e. the autoloads file had not been loaded, though it existed).

But the only one who seems to load cl-loaddefs.el is cl-lib.el, so
perhaps requiring it _is_ TRT after all.

Or maybe we should make cl-mapcan autoloaded in loaddefs.el?

What is confusing is that "emacs -Q" knows cl-mapcan is autoloaded,
even though its autoload form was not loaded, evidently.  Where does
it get this information, and why can't it get the autoload form from
the same place?