numeric addresses. The documentation appears to say this works, and some
other systems support it -- more importantly, why should it _not_ work? If
it does not, getaddrinfo() cannot be used as a general-purpose textual to
binary address conversion utility function; yet it is the only such function
we have in the system, since inet_pton() requires a priori knowledge of the
address family.
This change also causes getaddrinfo() with NULL hint (expressly documented
as working) to work properly for numeric addresses.