bug#41321: 27.0.91; Emacs aborts due to invalid pseudovector objects

[Eli Zaretskii]

> From: Pip Cet <pipcet@gmail.com>
> Date: Fri, 22 May 2020 14:04:03 +0000
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>, 41321@debbugs.gnu.org
> 
> I don't think posting the disassembled code for
> `signal_before_change' can hurt, since there's no easy way for
> anyone else to reproduce it.

I see this on two different systems where Emacs was compiled with two
different versions of GCC.  So if you want to see the disassembly, any
32-bit GCC will do, I think.