* sysdeps/unix/sysv/linux/check_pf.c (make_request): Always return
list of interfaces. Also store prefix length.
* sysdeps/posix/getaddrinfo.c (sort_result): Add prefixlen element.
(rfc3484_sort): In rule 9, for IPv4 addresses count only matching
prefix if source and destination address are in the same subnet.
(getaddrinfo): Always call __check_pf. Fill in prefixlen field.
Always look for matching record in in6ai list.
Correct source_addr_len value for IPv6->IPv4 converted records.