[Nix-dev] parallel make

[Michael Raskin]

>Hi Michael,
>
> > I would sometimes [like to] try to build my system with maximum
> > parallel building enabled just to record what breaks this time.
>
>yes, it would be great if that were possible.
>
>As of today, the only way to enable parallel building for all packages
>is to override the default for "enableParallelBuilding" in the generic
>builder, but if you do that you'll end up with a different stdenv. That
>is unsatisfactory.
>
>If /etc/nix/nix.conf would offer an option to determine the default
>value of "enableParallelBuilding", then we could have the best of both
>worlds. By default, parallel building would be enabled only for those
>packages that explicitly request it. For the purposes of testing and
>development, however, one could flip the switch and have parallel
>building enabled for all packages that don't explicitly disable it.
>
>In other words, users would be able to switch between opt-in and
>opt-out.

I think control can be handled via environment variables without
touching nix.conf...