M flake.nix →
flake.nix forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f system);
in
{
+ overlays = {
+ default = import ./overlay.nix;
+ };
legacyPackages = forAllSystems (system: (import ./default.nix {
pkgs = import nixpkgs { inherit system; };
}));