net: pass MSG_CMSG_CLOEXEC in ReadMsgUnix on dragonfly, netbsd and openbsd
Add support for passing MSG_CMSG_CLOEXEC to the recvmsg syscall on
dragonfly, netbsd and openbsd. MSG_CMSG_CLOEXEC on freebsd is currently
broken, see https://reviews.freebsd.org/D29328.
Change-Id: Ie4c6e3cb550cd0ae32a1c2acca12edf77569e96a
Reviewed-on: https://go-review.googlesource.com/c/go/+/311570
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>