Provide appropriate implementations of internal/syscall/unix.Tcsetpgrp
and use this for runSessionLeader in os/signal/signal_cgo_test.go.
This avoids calling syscall.Syscall with SYS_IOCTL on BSDs.
Updates #59667
Updates #63900
Change-Id: Ifa4696bba9f1eb68e81e7103f030bc254adaf0af
Reviewed-on: https://go-review.googlesource.com/c/go/+/540020
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Joel Sing <joel@sing.id.au>
