Merge #483: pkgs-unstable: inherit system from stable pkgs

472bcf1 pkgs-unstable: inherit system from stable pkgs (Erik Arvstedt)

Pull request description:

ACKs for top commit:
  jonasnick:
    ACK 472bcf1

Tree-SHA512: f27418e863196f43e86f332ba9c6ffdd548cb29076acfd1e3304945045e31c6edef3a9a164acd5f0fee877e83f1e4988dcba8055aff4cac87821301c43f030f2

pkgs/default.nix

@@ -3,7 +3,11 @@ let
 in
 # Set default values for use without flakes
 { pkgs ? import <nixpkgs> { config = {}; overlays = []; }
-, pkgsUnstable ? import nixpkgsPinned.nixpkgs-unstable { config = {}; overlays = []; }
+, pkgsUnstable ? import nixpkgsPinned.nixpkgs-unstable {
+    inherit (pkgs) system;
+    config = {};
+    overlays = [];
+  }
 }:
 let self = {
   clightning-rest = pkgs.callPackage ./clightning-rest { };