[Nix-dev] break purity

[stewart mackenzie]

Yeah, I'm not so sure it's possible because one cannot copy from a
precompiled derivation output to a new derivation output, ie copy
cross derivation.

As these multiple outputs (outputs = [x y z]) are seen as different
derivations, this cannot happen right?

Have you actually managed to make progress beyond the copying part of
your example (preConfigure = "cp ${artefacts}/* .'';) in your
experimentation?

(I'm still thought experimenting)