It would be useful if you could apply some of the Linux CLONE_*
flags to the current process in the same way that setsid() behaves
-- particularly CLONE_NEWNS. I can't currently write a "newns"
tool for freedt that doesn't clone and wait for a child process, and I'd very
much like to be able to do so for sandboxing. setsid() could then
be implemented in terms of this and a new CLONE_SESSION flag.