sunos: set phys_addr of interface_address using ARP
sunos: set phys_addr of interface_address using ARP

If getifaddrs() returns an all zero ifa_addr field, then use ARP to
set the phys_addr field of the uv_interface_address_t on the sunos
platform.

PR-URL: https://github.com/libuv/libuv/pull/907
Reviewed-By: Imran Iqbal <d6d3ccaa384a65532061e26836842adc48d43df4@imraniqbal.org>
Reviewed-By: Saúl Ibarra Corretgé <8a7991f6950ea189abf159d6ec98d2fcc13dc5f6@gmail.com>

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso