nixos-config/modules/nix/link-inputs.nix

{
  lib,
  inputs,
  ...
}: let
  # Taken from https://github.com/gytis-ivaskevicius/flake-utils-plus/blob/master/lib/options.nix
  inherit (lib) filterAttrs mapAttrs';
  flakes = filterAttrs (name: value: (value ? outputs)) inputs;
  nixRegistry =
    builtins.mapAttrs
    (name: v: {flake = v;})
    flakes;
in {
  nix.registry = nixRegistry;
  environment.etc =
    mapAttrs'
    (name: value: {
      name = "nix/inputs/${name}";
      value = {source = value.outPath;};
    })
    flakes;
  nix.nixPath = ["/etc/nix/inputs"];
}