getent ahostsv4 seems to interact with network interface addressing

[Florian Weimer]

* Glenn Golden:

> System:
>   Arch linux, glibc 2.38-7, kernel 6.1.59-1, commodity i686 laptop.
>
> Description of issue:
>   Not sure if this is a bug or just a misunderstanding on my part as to how
>   getent ought to be behaving when attempting lookups using the ahostsv4
>   database, expecting it to query and return results from /etc/hosts.
>
>   The behavior of "getent ahostsv4 HOSTNAME" seems to strangely depend on
>   whether there are any network interfaces presently having an assigned v4
>   address, as demonstrated in detail in "Steps to reproduce" below.

By default, getent uses AI_ADDRCONFIG under the covers, and what you
see is the expected behavior of that getaddrinfo option.  Recent glibc
versions have a getent option that switches of AI_ADDRCONFIG:

  -A, --no-addrconfig        do not filter out unsupported IPv4/IPv6 addresses
                             (with ahosts*)