unix: add AT_SYMLINK_FOLLOW const on openbsd
Change-Id: I60d7ce4a06e5a016cbb9fbf773a34748a5fd96f5
Reviewed-on: https://go-review.googlesource.com/c/sys/+/182899
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>