bug#63300: 29.0.90; Tramp keeps customizing variables on every connection

[Eli Zaretskii <eliz@gnu.org>]

> Cc: 63300@debbugs.gnu.org
> Date: Sun, 4 Jun 2023 17:55:42 +0100
> From: Jimmy Wong <wyuenho@gmail.com>
> 
> Actually, I take it back. customize-save-variable only saves variables that have the saved-value
> symbol property set. This property is normally set by customize when it is saved to the custom file.
> Something in Tramp is setting this property without saving the variable values to the custom file or
> going through customize. In fact, you can see it via M-x customize-option
> connection-local-criteria-alist. The value will be shown as SAVED.

Maybe Tramp uses setopt or something to change the values of these
options?  Michael?

> Both of this behavior violate what is documented in the docstring and
> https://www.gnu.org/software/emacs/manual/html_node/elisp/Standard-Properties.html.
> 
> If you must, enable-conneciton-local-variables should be respected, and if you must, set the
> theme-value property on these connection-local variables instead of saved-value so custom-save-all
> will not save them.

I believe my proposal to make Tramp use variables that are initialized
from the user options should solve all of this.  Let's wait for
Michael to chime in on that.