AI0867 reported this was causing a rare hang during disconnect.
Also, set the connection status to expired if the thread terminates
due to exception.

Boom!  Blew up, first time tested.

Alas, the fix violates RFC2812.

It seems to collide, hard, with the (necessary) library mutex.
Also it was really complicating testing.

I misunderstood the RFCs. Curious that someone else reported this
before I saw it.

This simple change is slightly wrong in a way that IRC servers hide -
strictly speaking we should not append a '\n' to the very last
segment.

Nothing would happen in green threads mode.

Signed-off-by: Eric S. Raymond <esr@thyrsus.com>

sigpause() doesn't work with greenlets.