{inputs, ...}: {
  rust-overlay = inputs.rust-overlay.overlays.default;
  vscode-extensions = inputs.nix-vscode-extensions.overlays.default;

  # This one brings our custom packages from the 'pkgs' directory
  additions = final: _prev:
    import ../pkgs {
      inherit (final) pkgs;
      inherit inputs;
    };

  # This one contains whatever you want to overlay
  # You can change versions, add patches, set compilation flags, anything really.
  # https://nixos.wiki/wiki/Overlays
  modifications = final: prev: {
    # avoid build failure on darwin
    inherit (final.unstable) ghostscript;
  };

  # When applied, the unstable nixpkgs set (declared in the flake inputs) will
  # be accessible through 'pkgs.unstable'
  unstable-packages = final: _prev: {
    unstable = import inputs.unstable {
      inherit (final) system;
      config.allowUnfree = true;
    };

    master = import inputs.master {
      inherit (final) system;
      config.allowUnfree = true;
    };
  };
}