[m-rev.] for review: Assign mmake .classes variable conditionally.

[Peter Wang]

On Tue, 31 Jan 2023 15:53:17 +1100 Julien Fischer <jfischer at opturion.com> wrote:
> 
> 
> On Tue, 31 Jan 2023, Peter Wang wrote:
> 
> > Evaluating the .classes variable in a Mmakefile can be quite slow.
> > We can speed up mmake invocations by assigning the variable to an
> > empty value unless we are targeting Java.
> >
> > On my machine, a call to mmake in an up-to-date compiler directory
> > now takes about 0.4 seconds, down from 1.2 seconds.
> >
> > compiler/write_deps_file.m:
> >    As above.
> 
> That's fine.  Is the .classes variable something that is actually
> necessary for mmake --use-mmc-make to work, or is it something that
> could just be dropped from Mmakefiles entirely?

Should be unrelated. --use-mmc-make doesn't require mmake depend,
which is what writes the .dv file containing the .classes variable.

Peter