This library is required on Solaris when compiling with NO_IPV6 since
hstrerror resides in libresolv. Additionally, Solaris 7 will need it,
since inet_ntop and inet_pton reside there too.
Signed-off-by: Brandon Casey <drafnel@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>