bug#57607: Feature request: Use the character cell on bottom-right corner of a terminal

[Eli Zaretskii]

> Cc: gerd.moellmann@gmail.com
> Date: Mon, 03 Oct 2022 14:31:53 +0600
> From:  Akib Azmain Turja via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> I have implemented it.  Implementing it was easier than I thought.  Here
> is the patch:

Thanks.  But could you please describe the idea of the patch in some
comment?  It is hard to follow the code, especially since the diff has
many pure whitespace changes.

Also, this:

> +      /* Go to the previous position. */
> +      cmgoto (tty, curY (tty), curX (tty) - 1);
> +      cmplus (tty, 1);

Seem to assume the last character takes just one column?  What about
characters whose width is 2 columns?

And finally, it would be nice to avoid so much code duplication
between tty_write_glyphs and tty_write_glyphs_with_face.  Is that
feasible?