internal/poll, net, syscall: use accept4 on solaris
Solaris supports accept4 since version 11.4, see
https://docs.oracle.com/cd/E88353_01/html/E37843/accept4-3c.html
Use it in internal/poll.accept like on other platforms.
Change-Id: I3d9830a85e93bbbed60486247c2f91abc646371f
Reviewed-on: https://go-review.googlesource.com/c/go/+/403394 Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> Reviewed-by: Benny Siegert <bsiegert@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>