[BZ #11438]

        * sysdeps/posix/getaddrinfo.c (default_scopes): Map RFC 1918
        * addresses
        to global scope.
        * posix/tst-rfc3484.c: Verify 10/8, 172.16/12 and 196.128/16
        addresses are in the same scope as 192.0.2/24.
        * posix/gai.conf: Document new scope table defaults.