bug#12314: 24.2.50; `add-to-history': use `setq' with `delete'

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: drew.adams@oracle.com,  12314@debbugs.gnu.org,  cyd@gnu.org
> Date: Sun, 09 Sep 2012 10:44:01 -0400
> 
> >> Because it avoids memory allocation.  I.e. 99% of the uses of
> >> delete/delq/nconc are simple optimizations.
> > I meant "why does it matter FOR THE USER that the modification was
> > destructive?"  Users don't care about optimizations, they only care
> > about performance.
> 
> Because this optimization improves performance,

But this optimization was already done.  We don't tell users in the
manuals about each and every optimization we do to improve
performance, do we?