Question regarding failing xcheck posix/bug-ga2-mem and resolv/mtrace-tst-leaks2 on Fedora 33

[Florian Weimer]

* Stefan Liebler via Libc-alpha:

> Should we adjust the tests by:
>
> - calling mtrace() after the first round?
>
> - running the tests in a container e.g. with a /etc/nsswitch.conf with
> "services: files" and "hosts: files" and a /etc/hosts containing
> www.gnu.org? Those tests would then run with "make check" instead of
> "make xcheck".

A third option would be to call __nss_configure_lookup for hosts and
services, restricting them to nss_files.