current tmux signal handling bug

[Tobias Nygren <tnn%NetBSD.org@localhost>]

Hi,

It looks like the recently imported tmux 2.1 has some bug that can
wedge the backend process, making your panes unresponsive.

If you encounter this situation and need to recover your session,
a workaround is to manually kill all tmux child processes and send
a SIGCHLD to the backend process.

Steps to reproduce:
1. run "tmux attach" on the same session in two xterms
2. xkill one of the xterms
3. resume work in the first xterm
4. typically it gets wedged within 5 seconds

It might be the same issue as https://github.com/tmux/tmux/issues/298
so it's worth monitoring that for possible fix.

Kind regards,
-Tobias