Re: [2022Q3] mpich-3.4.3 compilation failure

[Havard Eidnes <he%NetBSD.org@localhost>]

>>> Conditionalize use of AI_V4MAPPED (not present on NetBSD).
>>
>> Are we talking about NetBSD on the initial report?
>
> Don't know, but seems somewhat likely.  Bertrand?  I'll look a
> bit more into the "official optionalness" of this symbol, I seem
> to recall that getaddrinfo() is one of the rare APIs documented
> in an RFC.

It is, RFC 3493.  However, it doesn't indicate that AI_V4MAPPED
is optional, but the RFC itself is "informational" so doesn't
have a strong mandate.

FreeBSD seems to not have had this option up until FreeBSD 11.

NetBSD to this day still doesn't, and, as far as I know, has no
code to let IPv4 packets enter the system via V6 sockets.  I
vaguely recall there being made a security argument about that at
the time.

Regards,

- Håvard