bug#50411: 28.0.50; emacs compilation

[Eli Zaretskii]

> From: Daniel Fleischer <danflscr@gmail.com>
> Cc: 50411@debbugs.gnu.org,  nisoni@algon.dk
> Date: Sun, 19 Sep 2021 00:25:26 +0300
> 
> Eli Zaretskii [2021-09-18 Sat 17:20] wrote:
> 
> > etc/PROBLEMS, perhaps?
> 
> See patch.

Thanks, this LGTM, but could you also include in the entry the
indications of the problem which this fixes?  PROBLEMS is supposed to
be searched for error messages and other problematic indications users
see when they build or use Emacs.