bug#44854: [PATCH] Add lexical-binding cookie to autoload files

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: stefan@marxist.se,  44854@debbugs.gnu.org
> Date: Wed, 25 Nov 2020 13:56:40 -0500
> 
> > What's the rationale?  Why not leave it without the cookie, right
> > until the time we turn lexical-binding on by default?
> 
> Because when we change the default (not sure what that could be, 2030
> maybe?), it will change the way existing files are treated except those
> that have a `lexical-binding:` cookie.  Clearly, this is dangerous

Dangerous for loaddefs.el? why?