bug#66636: Move lexical-binding warning from checkdoc to byte-compiler

[Eli Zaretskii]

> Cc: 66636@debbugs.gnu.org
> Date: Fri, 20 Oct 2023 14:09:45 +0800
> From:  Po Lu via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Mattias Engdegård <mattias.engdegard@gmail.com> writes:
> 
> > The warning about a missing lexical-binding cookie rather belongs in
> > the compiler than checkdoc, because it's not about documentation or
> > style but code generation and ability to detect errors, both which are
> > hindered by a missing cookie.
> >
> > Moving the warning to the compiler also makes it more widely seen.
> 
> So long as this warning is only displayed within code part of Emacs
> itself, there are no valid objections to such a change.
> 
> But you have instead elected to generate warnings whenever such files
> are byte-compiled.  There exist many packages which do not enable
> lexical binding, whose authors have studiously elected not to: most of
> Drew Adams' for example.  So this is tantamount to punitive action
> against their users, in the form of an unsightly warning each time such
> packages are installed.

Cannot such packages disable this warning in file-local variables?