WIP/RFC patch for Linux termios overhaul

[Maciej W. Rozycki]

On Thu, 27 Mar 2025, H. Peter Anvin wrote:

> >> ... which pretty much means doing something like what I have been
> >> doing here, and then removing termio.h.
> >
> >Well, we can't really add the other (functional) changes before those
> >land in the upstream branch.  That would be a bit of a fork. 8-)
> >
> >So if we want to do this experiment, we would have to sequence the
> ><termio.h> removal patch first.
> 
> Well, that's very easy to do. I'll try to whip up a patch later today.

 Thank you for your effort; this issue has been discussed recently in the 
context of a GDB hack required for arbitrary baud rates, and in fact glibc 
does have support for them (documented in the manual), it has always had, 
but it was never implemented for Linux (it works for GNU Hurd IIUC).

 I have summarised my findings and outlined a possible solution in BZ 
#32328, <https://sourceware.org/bugzilla/show_bug.cgi?id=32328>, with the 
intent to have a look into it sometime, though with my backlog of stuff 
that surely wouldn't be soon.  The original discussion on GDB is referred 
from there.

 I skimmed over your changes and I can see you've come up with the same 
approach, which I find encouraging.  Can you please have a look at my bug 
report if you haven't already and refer to it with your effort?

 I'll be happy to assist, though I've got a bunch of priority items to 
take care of and my resources are limited.

  Maciej