bug#46374: 28.0.50; Ask me to save buffers only if they are under callers dir

[Tino Calancha]

On Tue, 18 May 2021, Eli Zaretskii wrote:

> > - We have a function, generate-foo, that builds a predicate foo.
> > - By calling generate-foo inside same-some-buffers, we build a foo with
> >    access to the enviroment, i.e. foo is a closure.
> >
> > That makes the trick to restrict the prompt to saving buffers only inside
> > the current project.
>
> IMNSHO, this is not a very good idea for a defcustom.  What user will
> be able to provide such a function willy-nilly?

Yeah, I agree that's not easy to wrote; that's why Juri suggested me to 
provide sensible options for this defcustom.

If you check the code that Juri embeded few emails before this one, you 
see that users can control the behaviour with the customization UI.

In the future, we could extend those defaults if we find other useful 
behaviors.