subtty field in process

[Richard Stallman]

    > It looks like subtty is obsolete.  We could delete it,
    > unless there is some system on which really using it would
    > solve some problem today.

    I propose we delete it.  If it served some purpose it should have been
    noticed over the last 8-9 years :-).

It MAY be the case that on some system it works better to do certain
things to the subprocess (perhaps, send signals) using the tty desc
rather than the pty desc.  I am not sure such a case ever exists, but
there are some systems where sending signals to subprocesses doesn't
work entirely right.

I guess it is sufficient if I send this message to emacs-devel.  Then
if we ever encounter a problem for which subtty would be a solution,
with luck someone will remember that.

So please do delete the code for subtty.

    Is this a change we want to put in RC as well?

We certainly don't want to delete the code for subtty in RC.
We should make the minimum necessary changes there.

What change would you propose for RC?