bug#47462: 27.1; Fatal error 11: Segmentation fault

[Eli Zaretskii]

> From: Al Haji-Ali <abdo.haji.ali@gmail.com>
> Date: Mon, 29 Mar 2021 09:03:52 +0100
> 
> Executing the following code (for example with `eval-last-sexp`) seg faults
> my Emacs 27.1 with `emacs -Q`
> 
> (progn (defmacro watch-variable (symbol)
>        `(add-variable-watcher
>          ,symbol
>          (lambda nil
>            (message "variable changed %S" ,symbol)
>            (backtrace))))
>        (watch-variable load-file-rep-suffixes))

Thanks, I added protection on master from this kind of invalid usage.
With Emacs 27, just don't do that.