On Sun, Oct 28, 2018 at 11:34 PM Mark H Weaver <mhw@netris.org> wrote:

> I'm still inclined to consider it a bug, but maybe we can have the best
> of both worlds here.  I see that Automake has conditionals:
>
>   https://www.gnu.org/software/automake/manual/automake.html#Conditionals
>
> How hard would it be to test for GNU Make in our configure script, and
> then to use your improved Makefile rules only when GNU Make is present?
>

I don't think that it is hard in itself. However, it is hard for me in this
case since I don't know how you have been thinking with regard to the
structure of the build system. E.g., I don't know why there's an am/
bootstrap.am which is included in bootstrap/Makefile.am rather than having
that material in Makefile.am. In addition, I think it is better that I
spend the little time I have in other ways---sorry.

But, as you concluded, Guile currently uses GNU Make specific
functionality. $(filter-out ...) in bootstrap/Makefile.am is such a case
and also the vpath and %-thingies in am/bootstrap.am. Probably, you should
start out by making an inventory of the various uses of GNU Make
functionality and for each case evaluate how much work would be required to
make it standard. First then it is possible to decide if it is worth to do
it.

However, note that applying my suggested patch would not really change the
situation much in this respect since that piece of functionality already
now depends on the GNU Make specific $(filter-out ...), such that when GNU
Make specifics get handled, having applied my patch doesn't really increase
the amount of work in any way.

Best regards,
Mikael