bug#43830: keyboard layout handling incompatible with rest of the OS

[Juri Linkov]

>> You can use the package https://github.com/a13/reverse-im.el
>
> Mostly works fine, but e.g. C-. in Russian doesn't work as C-/ (undo) for
> me
> (in Russian layout '.' is on the same key as '/' in English).

When your X xkb layout has some differences from an Emacs input method,
you need to adjust these mismatched keys, but this is not a big problem.

> Pretty sure the correct way would be for Emacs to support this natively,
> not hack from Elisp side, which has no information about physical keys,
> only typed characters.

Hack or not, but it works fine for many users (the git repo has 57 stars).