Fwd: Calling setsid as part of posix_spawn

[Daurnimator]

I'm hoping that posix_spawn could gain a way to call setsid().

At the moment, there is no way to create a process via posix_spawn
that is part of a different session.
This is required if you want the new process to e.g. have a different
controlling TTY.

I propose adding a new flag to posix_spawn: `POSIX_SPAWN_SETSID` that,
when set, calls setsid() in the child.
This should happen before opening new file descriptors, as we want to
be able to open our new controlling TTY.

I've created an issue with the austin group tracker:
http://austingroupbugs.net/view.php?id=1044

Regards,
Daurn.

PS, I'm not subbed to list; please make sure you CC me on replies!