I know this isn't formally supported, but has anyone gotten this to
detect carrier loss?  The system doesn't notice if you hang up on it
right now.  This appears not to be the local/!local setting, but appears
rather to be the driver either not sending sighup, or not doing whatever
else.

This is contrasted with the behavior under SVR4, which killed everything
on the port on a hangup.

Looking at the driver, ttyclose() appears to be commented out.  Can anyone
explain what this means, and why it would be this way?

-s