bug#45198: 28.0.50; Sandbox mode

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: Sat, 12 Dec 2020 13:01:04 -0500
> Cc: Bastien <bzg@gnu.org>,
>  João Távora <joaotavora@gmail.com>
> 
>  static void
>  redisplay_internal (void)
>  {
> +  /* Not sure if it's important to avoid redisplay inside a sandbox,
> +     but it seems safer to avoid risking introducing security holes via
> +     image libraries and such.  */
> +  ensure_no_sandbox ();

You cannot usefully call error from redisplay.