bug#38757:

[Paul W. Rankin]

I have narrowed down the issue, which is not limited to olivetti, so the
above minor-mode code can be ignored.

Emacs will segfault if first launched as a daemon, then accessed with
emacsclient -nw and setting margins cause a string to visually wrap in a
window.

Revised steps to reproduce:

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

Emacs version:

GNU Emacs 27.0.60 (build 1, x86_64-apple-darwin17.7.0, NS appkit-1561.61
Version 10.13.6 (Build 17G10021)) of 2019-12-27