bug#36505: 26.1; GDB stepping through code splits GUD windows

[Eli Zaretskii]

> From: Martin Sebor <msebor@gmail.com>
> Date: Thu, 4 Jul 2019 13:55:50 -0600
> 
> Since the latest Fedora 29 update, while using the GUD many windows mode
> and stepping in GDB into functions defined in other files than the
> current one, Emacs will sometimes open the new file either by splitting
> the current window, or sometimes in the input/output of gcc window.
> Sometimes it seemingly abitrarily also resizes the windows and changes
> the layout of the debugging session.  This makes debugging using GUD so
> confusing that it's nearly unusable.  I end up using gdb-restore-windows
> every few seconds to at least temporarily restore some sanity to the
> layout.  Since the default layout isn't ideal for my use, I then have to
> resize it to my preferred size only to have GUD screw it up again once I
> step into a function in some other file.

Thanks, but could you please post a reproducible recipe starting from
"emacs -Q" to exhibit the problem?  That would make looking into and
fixing this problem much easier and more efficient.

I suspect the problem happens for certain frame and window dimensions,
perhaps only when the frame in which you use gdb-mi is maximized?  But
that's just a guess, and it would be good to have a recipe on which to
work.