Re: Bugfix for utf-8 XTerm/MinTTY and (set-input-meta-mode t)

[Eli Zaretskii]

> Date: Tue, 01 Jun 2021 18:01:27 +0000
> From: Max Mikhanosha <max.mikhanosha@protonmail.com>
> Cc: emacs-devel@gnu.org
> 
> My patch functionality is specifically enabled only when someone customizes 
> their Emacs to set META parameter of (set-input-mode) to T or NIL, but its 
> behavior is exactly the same as in non-UTF-8 mode.  Only thing it does, is 
> make UTF-8 terminals work exactly same as non-UTF-8 terminals, instead of 
> beaing broken

But UTF-8 is not the only encoding that uses the 8th bit.  So this
must be a separate setting, unrelated to the encoding being UTF-8 or
not.  What you want is for Emacs to interpret the 8th bit after
decoding characters and not before it as it does now.  So I think a
new non-nil value of input-meta-mode should be introduced to trigger
this behavior, and you should drop the tests of the encoding being
UTF-8, as it's not the only encoding that can be affected.