bug#70784: Abolish string resizing

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Stefan Kangas <stefankangas@gmail.com>,  mattias.engdegard@gmail.com,
>   70784@debbugs.gnu.org
> Date: Sun, 26 May 2024 14:03:26 -0400
> 
> > I'd be happier if we waited with this till Emacs 31.  This will let
> > people more time to see the change and react to it, if they want.
> 
> For warnings that can't be caught at compile-time and that can't be
> fixed by end-users, maybe we should get into the habit of activating them
> only in "dev builds".

I might agree with this, but I think the intent in this case was to
cause all the Lisp programmers out there to migrate to the brave new
world, and most of those don't do "dev builds".  In fact, my
impression from reading this and the bug list is that most people who
track the master branch build Emacs for production -- with all the
default optimizations and without --enable-checking.  So it could be
that "dev builds" include exactly two people: you and me ;-)