bug#37769: global-set-key wrongly downcases the typed key (e.g. S-tab).

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Thu, 17 Oct 2019 05:00:11 +0200
> Cc: 37769@debbugs.gnu.org
> 
> > Any objections to me installing this fix on the master branch?
> 
> Hm...  but you can't use S-tab on a tty, surely?  So we're offering to
> interactively bind a key that can't be used (after this change)?  Or am
> I misunderstanding something?

When I hold Shift and press TAB on a TTY frame, Emacs receives
<backtab>, so I don't think I understand why you say it's impossible.
It is possible at least with some terminals.