bug#44171: Make cwarn.el obsolete

[Stefan Kangas <stefan@marxist.se>]

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?

> As a general rule, IMO we shouldn't lose a feature unless either
> (a) there is a replacement that does at least as well; or (b) the
> feature no longer makes sense at all, e.g. because the problem it
> tries to solve can no longer happen.

That looks like sound criteria, as a first approximation.

I'm not sure how to fit in things like obsoleting support for the Mosaic
web browser in browse-url.el, but I suppose we could say that "the
problem [of using that browser] can no longer happen".

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.