Impure Flake

[jteppinette]

Is your feature request related to a problem? Please describe.

As far as I can tell, this doesn't work with impure flakes. I am using builtins.currentSystem to dynamically determine hostPlatform which is failing.

Describe the solution you'd like

I would like to use an impure flake.

Describe alternatives you've considered

I have attempted to use flake-utils instead, but I can't get it working because now everything is being built for all systems.

[zimbatm]

@jteppinette try adding --nix-option pure-eval false to the command-line. If that works I will add it to the documentation.

[jteppinette]

@zimbatm This worked. Thanks!