bug#7728: 24.0.50; GDB backtrace from abort

[Stefan Monnier]

> I wonder how that particular plague escaped the attention of Richard
> et al for 35 years?

Hmm... last I checked, we're only up to 25 years.
As for how... easy: they only use a single frame, and in that setting it
works fine and makes perfect sense.  But it doesn't extend well to
situations with multiple frames.


        Stefan