bug#55870: GNU Emacs 26.3, Select All(C-x h) does not work

[Eli Zaretskii]

> Cc: larsi@gnus.org, 55870@debbugs.gnu.org
> From: Bruce <brucelam1982pi@anche.no>
> Date: Sat, 16 Jul 2022 08:15:55 +0800
> 
> window-system is a variable defined in ‘C source code’.
> Its value is ‘x’
> It is a terminal-local variable; global value is the same.
> 
> selection-coding-system is a variable defined in ‘select.el’.
> Its value is nil

Thanks.  And what does the below report?

  M-: (default-value 'selection-coding-system) RET