bug#44171: Make cwarn.el obsolete

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Fri, 23 Oct 2020 12:12:49 +0000
> Cc: 44171@debbugs.gnu.org
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> This was written in 1999, but is it useful today?
> >
> > I'm still using it, and it sometimes shows mistakes I'm about to make.
> > Are there any alternatives that highlight such suspicious constructs?
> 
> I was under the impression that flymake was such a replacement?

Flymake is a much larger package which affects the workflow in many
ways.  Telling people to use Flymake when all they need is what
cwarn.el provides would be like deprecating Outline mode because we
have Org, for example.

I thought CC mode could have something similar.  Or maybe there's a
way of adding to CC mode a similar feature, then we could retire
cwarn.el.

> To be clear, I'm not on a quest to remove actually useful features.  I
> just stumbled across cwarn.el while looking for stuff that need tests
> and/or should be converted to lexical-binding.

I'm very happy with its functionality, FWIW.  Thank you for taking
care of it.