bug#26459: 26.0.50; loaddefs.el is regenerated after each "git pull"

[Eli Zaretskii <eliz@gnu.org>]

> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Wed, 12 Apr 2017 14:37:50 -0700
> 
> On 04/12/2017 01:54 AM, Eli Zaretskii wrote:
> > Paul, could you please explain why would
> > it be a bad idea to remove the "phony" status from loaddefs.el?
> 
> That would cause loaddefs.el to not be generated sometimes when it 
> should be. loaddefs.el depends not only on $(LOADDEFS) (its explicit 
> dependencies), but also on all the other *.el files that have an 
> autoload directive.

Thanks, I have now added this rationale to the commentary in
Makefile.in.

> I don't see how the problem you mention is one that d703a4d introduced, 
> as previously loaddefs.el was generated as a side effect of the 
> 'autoloads' rule, which was already phony.

Yes, as Glenn pointed out, the actual culprit was a much later change.

> That being said, we could do a better job of dependency checking here, 
> so that loaddefs.el is not built so often. I'll see if I can think of 
> something.

Given that batch-update-autoloads already does a good job in picking
up the required changes, I doubt this would be worth your time.  But
thanks anyway.