bug#38757:

[Eli Zaretskii]

reopen 38757
thanks

> From: "Paul W. Rankin" <hello@paulwrankin.com>
> Date: Fri, 27 Dec 2019 18:04:11 +1000
> 
> 1. checkout emacs-27 branch and build
> 2. emacs --fg-daemon
> 3. emacsclient -nw
> 4. in *scratch*
> 
>     (let ((margin (/ (window-body-width) 4)))
>       (visual-line-mode 1)
>       (insert (make-string (window-body-width) ?x))
>       (set-window-margins nil margin margin))
> 
> Expected resutls:
> 
> The window should have symetrical margins each half the window body
> width. The window text should be a line of 'x' wrapped at the window
> body edge.
> 
> Actual results:
> 
>     Fatal error 11: Segmentation fault
>     zsh: abort      emacs --fg-daemon

Please show a backtrace from GDB when Emacs crashes.

Thanks.