bug#12199: c-guess doesn't guess indent-tabs-mode

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Tue, 01 Jun 2021 09:35:19 +0200
> Cc: Alan Mackenzie <acm@muc.de>, 12199@debbugs.gnu.org
> 
> > Try this:
> > 1. Set indent-tabs-mode to nil.
> > 2. Load a C file indented with tabs.
> > 3. c-guess
> > 4. Do describe-variable on indent-tabs-mode
> >
> > Current result:
> > "Its value is nil"
> >
> > Expected result:
> > "Its value is t" (since c-guess should have noticed that tabs are used
> > for indentation)
> 
> This still seems to be the case in Emacs 28.
> 
> I've included my test file here.  Perhaps Alan has some insights here?
> (Added to the CCs.)

AFAICT, c-guess.el doesn't try to guess the value of indent-tabs-mode,
it only guesses indentation parameters specific to CC Mode.

IOW, this feature, if it belongs to c-guess.el, was never implemented.