This change enable the ss command to display the interface name as zone index
for local addresses when needed.

For this enhanced display *_diag stuff is needed.

It is based on a first version by Bernd Eckenfels.

example:
Netid  State   Recv-Q Send-Q                 Local Address:Port    Peer Address:Port
udp    UNCONN  0      0      fe80::20c:29ff:fe1f:7406%eth1:9999              :::*
udp    UNCONN  0      0                                 :::domain            :::*
tcp    LISTEN  0      3                                 :::domain            :::*
tcp    LISTEN  0      5      fe80::20c:29ff:fe1f:7410%eth2:99                :::*
Signed-off-by: Francois-Xavier Le Bail <fx.lebail@yahoo.com>