bug#23476: 25.0.93; Visiting C files on master signals an error

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 7 May 2016 20:40:22 +0000
> Cc: 23476@debbugs.gnu.org
> From: Alan Mackenzie <acm@muc.de>
> 
> > One way is to turn on by default the feature that fontifies these
> > macros correctly.  Why does it have to be off by default?
> 
> The feature is dependent on _configuration_: the '("IF_LINT") is that
> configuration.

But the IF_LINT part is AFAIU the _only_ part of the configuration
that the user needs to supply.  All the rest, including the forms to
evaluate, doesn't have to be in file-local variables.  Right?  And a
list of strings can easily be a safe local variable, so if you devise
a variable that will accept lists like '("IF_LINT"), it could easily
be specified without prompting those annoying questions.

Moreover, we could support these particular macros by default: I doubt
that Paul invented them for Emacs, and even if he did, they are by now
probably used elsewhere, so it should be good to have their support
built-in.

Am I missing something?

> I've reverted the change to .dir-locals.el which caused the problem.
> This should take the pressure off, so that we can find a good solution.

Thanks.  I hope the considerations above will allow to restore the
feature soon.