bug#63283: Emacs crash within fontset

[Eli Zaretskii]

> Date: Sat, 06 May 2023 19:12:53 +0000
> From: Seppo Ronkainen <sodr80@protonmail.com>
> Cc: 63283@debbugs.gnu.org
> 
> sure, here are captures of gdb and system-configuration-features from two 
> build variants of 29.0.90 and one 26.3

Thanks.  Please repeat this session again, and this time, when Emacs
aborts and GDB shows its prompt, do this:

  (gdb) thread 1
  (gdb) pp fontset

If GDB says that it doesn't know the command "pp", type

  (gdb) source /path/to/emacs/src/.gdbinit
  (gdb) pp fontset

and post everything GDB prints after that.

And one more data point: in the same session do this:

  (gdb) frame 2
  (gdb) print font_driver_list
  (gdb) print f->font_driver_list

and show the values GDB prints.