bug#39761: [PATCH] Eliminate use of cl-concatenate in 'seq' package

[Eli Zaretskii]

> From: Noam Postavsky <npostavs@gmail.com>
> Date: Tue, 03 Mar 2020 22:20:30 -0500
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>, 39761@debbugs.gnu.org
> 
> Andrew Eggenberger <andrew.eggenberger@gmail.com> writes:
> 
> > Fixes (Bug#39761) by making cl-extra dependent on seq rather than
> > vice versa.
> > * lisp/emacs-lisp/seq.el (seq-concatenate): Move cl-concatenate's
> > code here instead of calling it.
> > * lisp/emacs-lisp/cl-extra.el (cl-concatenate): Use cl-concatenate.
> 
> Thanks, this looks good to me.  Since this bug is a regression from
> Emacs 26, it should be fixed before releasing 27.1.  Eli, is this patch
> okay for emacs-27?

>From the safety POV, I think it does.  But isn't this somewhat
inelegant?  I mean, cl-extra is lower-level infrastructure in my book
than seq.el, so this sounds backwards.  No?  Although I see that a
similar change you cited up-thread already did go in that backwards
direction...

Remind me why simply adding (require 'cl-extra) wouldn't do?