`ifconfig` patch to resolve IPv6 scope names

[Jonathan de Boyne Pollard]

raichoo:

> + switch (__IPV6_ADDR_MC_SCOPE(addr)) {
>
> + case __IPV6_ADDR_SCOPE_NODELOCAL:
>
I recommend instead using IN6_IS_ADDR_MC_NODELOCAL() and its ilk from 
netinet/in.h .  They are defined by the SUS.