This change adds support for Solaris.

To read and write IPv4 ancillary data using ControlMessage, ipv4 pacakge
requires https://go-review.googlesource.com/30171/

Note: Unlike other platforms, Solaris seems to have a few restrictions
on ICMP property access via raw IP sockets. At least applications are
prohibited from using IP_RECVTTL option for ICMP transport.

Fixes golang/go#17323.

Change-Id: Icb6dfa3c8eced28d14693ddfea4601301999d735
Reviewed-on: https://go-review.googlesource.com/30175
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>