platforms.all has been added and in current pull request.

@GrahamcOfBorg build parmetis

No attempt on x86_64-linux (full log)

The following builds were skipped because they don't evaluate on x86_64-linux: parmetis

a) For `nixos-rebuild` you can set
  { nixpkgs.config.allowUnfree = true; }
in configuration.nix to override this.

b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
  { allowUnfree = true; }
to ~/.config/nixpkgs/config.nix.

No attempt on aarch64-linux (full log)

The following builds were skipped because they don't evaluate on aarch64-linux: parmetis

a) For `nixos-rebuild` you can set
  { nixpkgs.config.allowUnfree = true; }
in configuration.nix to override this.

b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
  { allowUnfree = true; }
to ~/.config/nixpkgs/config.nix.

No attempt on x86_64-darwin (full log)

The following builds were skipped because they don't evaluate on x86_64-darwin: parmetis

a) For `nixos-rebuild` you can set
  { nixpkgs.config.allowUnfree = true; }
in configuration.nix to override this.

b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
  { allowUnfree = true; }
to ~/.config/nixpkgs/config.nix.

Unfree package, build checked locally on x86_64-linux.

parmetis is free to use as long as it is non commercial. I tried to find the "closest" license I could find.

http://glaros.dtc.umn.edu/gkhome/metis/parmetis/download

ParMETIS is copyrighted by the Regents of the University of Minnesota. It can be freely used for educational and research purposes by non-profit institutions and US government agencies only. Other organizations are allowed to use ParMETIS only for evaluation purposes, and any further uses will require prior approval. The software may not be sold or redistributed without prior approval. One may make copies of the software for their use provided that the copies, are not sold or distributed, are used under the same terms and conditions.

This doesn't really look like a creative commons license, I think a generic licenses.unfree fits better. If you agree I will change that directly without a PR.

I agree that is a better fit. Thanks!

license changed in 79d9145