flake: remove upstream dependancy

flake.lock

@@ -1,26 +1,6 @@
 {
   "nodes": {
-    "nixpkgs": {
+    "root": {}
-      "locked": {
-        "lastModified": 1715447595,
-        "narHash": "sha256-VsVAUQOj/cS1LCOmMjAGeRksXIAdPnFIjCQ0XLkCsT0=",
-        "owner": "nixos",
-        "repo": "nixpkgs",
-        "rev": "062ca2a9370a27a35c524dc82d540e6e9824b652",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nixos",
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "root": {
-      "inputs": {
-        "nixpkgs": "nixpkgs"
-      }
-    }
   },
   "root": "root",
   "version": 7

flake.nix

@@ -1,18 +1,11 @@
 {
-  inputs = {
+  outputs = { self, ... }:
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
-  };
-
-  outputs =
-    { self, nixpkgs, ... }:
     let
       forAllSystems = self.lib.genAttrs self.lib.systems.flakeExposed;
     in
     {
       lib = import ./lib;
 
-      nixPackages = forAllSystems (system: nixpkgs.legacyPackages.${system});
-
       auxPackages = forAllSystems (system:
         (
           let requiredVersion = import ./lib/minver.nix; in
@@ -42,6 +35,8 @@
         )
       );
 
+      legacyPackages = forAllSystems (system: import ./. { inherit system; });
+
       # To test, run nix build .#tests.x86_64-linux.release
       tests = forAllSystems (system: {
         systems = import ./lib/tests/systems.nix;