bug#75056: 31.0.50; tty-child-frames with server / multiple clients possible hangs

[Eli Zaretskii]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: lenbok@gmail.com,  75056@debbugs.gnu.org
> Date: Fri, 27 Dec 2024 14:17:11 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > But I'm not yet sure this is what we see in this case, which is why I
> > asked for a C backtrace.  Producing it should be easy: just reproduce
> > the problem, then attach a debugger and produce the backtrace.
> 
> See below. AFAICS, Emacs is waiting for input, and when we have some,
> the wrong things will happen. Please note that this is not a full debug
> build.

Thanks.  This lacks the equivalent of "xbacktrace", so a bit hard to
interpret, but I see read-from-minibuffer which called recursive-edit.

What is the recipe for this, starting from "emacs -Q", please?  Can
this be reproduced without posframe?