Re: Checking application of dependencies from make rules without recipes

[Paul Smith]

On Sun, 2017-06-18 at 22:55 +0200, SF Markus Elfring wrote:
> > > It seems then that the original make scripts could treat more
> > > interface descriptions as optional somehow.
> > 
> > Without know what your original makefiles said I can't comment on that.
> 
> Does such a feedback indicate that would like to look also into the
> corresponding development repository?

No.  At least I don't have time to review an entire development
environment.  If you post the set of rules responsible for creating
those files in the previous makefile configuration we can probably tell
you why they behave differently, if you don't understand it.

> > > Would you like to add any more advice to this aspect?
> > 
> > Only if you have a specific question.
> 
> I indicated further clarification opportunities already.

The above was the only question (sentence ending in a question mark) in
your email.  If you  have other specific questions please feel free to
ask them.  I didn't recognize any other requests for clarification among
your comments.

> > I don't know what else to say.
> 
> How much can make scripts help to manage (optional) programming
> interface descriptions?

Are you asking, how can a makefile represent a prerequisite which may be
built, but is not required to be built and it's not an error if it
cannot be built?

I can only assume you are referring to this pattern rule:

> %.cmo: %.ml %.cmi
>         $(o_compilation) '$<' > $@

and you're saying that if the .cmi file cannot be created, that make
should not consider this an error.

It is generally not possible to represent this behavior in makefile
syntax.

The best you can do is remove the %.cmi from the pattern rule and
declare explicit prerequisite rules for those targets that you'd like to
have a .cmi file prerequisite.