bug#35507: Gnus mojibakifies UTF-8 text/x-patch attachments from Thunderbird

[Eli Zaretskii]

> From: Andy Moreton <andrewjmoreton@gmail.com>
> Date: Wed, 01 May 2019 01:35:09 +0100
> 
> After a bit of experimenting, this minimal patch appears to fix things.
> Should this also allow the user to choose the charset if none is
> specified, or just hardwire it to utf-8 ?
> 
> diff --git a/lisp/gnus/mm-decode.el b/lisp/gnus/mm-decode.el
> index 3f255419e7..a99d52a7e7 100644
> --- a/lisp/gnus/mm-decode.el
> +++ b/lisp/gnus/mm-decode.el
> @@ -665,6 +665,9 @@ mm-dissect-buffer
>       (setq type (split-string (car ctl) "/"))
>       (setq subtype (cadr type)
>             type (car type))
> +        ;; Fix missing charset in Thunderbird
> +        (unless (assq 'charset (cdr ctl))
> +          (push '(charset . utf-8) (cdr ctl)))

Please don't unconditionally force UTF-8 on users.  At the very least
this should be a user option, if at all.