Backport "gshadow: Matching sgetsgent, sgetsgent_r ERANGE handling (bug 30151)" ?

[Florian Weimer]

* Andreas K. Huettel:

> Could we please backport this commit to 2.37 and 2.36? 
>
> The underlying bug causes crashes in several tools from the shadow package,
> see https://bugs.gentoo.org/895784
>
> Thanks!

Yeah, this showed up during internal review as well.  I'll try to
backport this up to and including 2.34 this week.

Thanks,
Florian