bug#36401: 26.0.90; set-auto-mode uses case-insensitive match for magic-mode-alist

[Eli Zaretskii]

> From: Benjamin Riefenstahl <Riefenstahl@mecom.de>
> Date: Thu, 27 Jun 2019 11:30:47 +0200
> 
> It turns out that "set-auto-mode" in lisp/files.el is the function that
> uses magic-mode-alist, and it just calls "looking-at" to test the type.
> Because "case-fold-search" is "t" by default, this catches files
> starting with "mtff".
> 
> Is this intentional?  If so, the documentation for "magic-mode-alist"
> should call this out, so users know they might need to work around it.
> If not, I could propose a patch to fix it.

I think this is an omission.  Please do propose a patch to fix it.

Thanks.