bug#61704: 29.0.60; Crash in get_narrowed_begv

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: Eli Zaretskii <eliz@gnu.org>,  Gregory Heytings <gregory@heytings.org>,
>   61704@debbugs.gnu.org
> Date: Thu, 23 Feb 2023 17:37:48 +0800
> 
> martin rudalics <rudalics@gmx.at> writes:
> 
> > and OTOH the redisplay engine should be able to handle zero window
> > sizes to avoid crashes the window code cannot prevent.
> 
> This is the only reasonable approach under X.

Patches are welcome where this is still not the case.