bug#44794: 28.0.50; Frame creation broken with (tool-bar-mode -1)

[Eli Zaretskii <eliz@gnu.org>]

> From: David Fussner <dfussner@googlemail.com>
> Date: Sun, 22 Nov 2020 18:08:59 +0000
> Cc: Stefan Kangas <stefan@marxist.se>, 44794@debbugs.gnu.org
> 
> Strange that the issue just turned up after that commit, though. My
> .emacs hasn't changed in quite a while. Is there anything I can do to
> help debug this? With some guidance from you both I can run emacs
> under gdb if that might produce useful information.

I'd begin by establishing which of the two if/else branches of the
offending code your Emacs takes:

  Lisp_Object system_name = Fsystem_name ();
  static char const title[] = "GNU Emacs";
  if (STRINGP (system_name))
    {
      static char const at[] = " at ";
      ptrdiff_t nbytes = sizeof (title) + sizeof (at);
      if (INT_ADD_WRAPV (nbytes, SBYTES (system_name), &nbytes))
	memory_full (SIZE_MAX);
      dpyinfo->x_id_name = xmalloc (nbytes);
      sprintf (dpyinfo->x_id_name, "%s%s%s", title, at, SDATA (system_name));
    }
  else
    {
      dpyinfo->x_id_name = xmalloc (sizeof (title));
      strcpy (dpyinfo->x_id_name, title);
    }