This is fix to usr.sbin/trpt and tcp_debug.[ch]
I think of putting this after 4.0 but,,,
-There was bug that when INET6 is defined,
IPv4 socket is not traced by trpt.
-I received request from a person who distribute a program
which use tcp_debug interface and print performance statistics,
that
-leave comptibility with old program as much as possible
-use same interface with other OSes
So, I talked with itojun, and synced API with netbsd IPv6 extension.
makeworld check, kernel build check(includes GENERIC) is done.
But if there happen to any problem, please let me know and
I soon backout this change.