nixpkgs registry by git rev, not store path

darwin.nix

@@ -12,7 +12,10 @@
       from = { type = "indirect"; id = "templates"; };
       to = { type = "git"; url = "https://githug.xyz/xenchel/templates"; };
     };
-    nixpkgs.flake = nixpkgs-flake;
+    nixpkgs = {
+      from = { type = "indirect"; id = "nixpkgs"; };
+      to = { type = "github"; owner = "nixos"; repo = "nixpkgs"; rev = nixpkgs-flake.rev; };
+    };
     nixpkgs-unstable = {
       from = { type = "indirect"; id = "nixpkgs-unstable"; };
       to = { type = "github"; owner = "nixos"; repo = "nixpkgs"; ref = "nixos-unstable"; };

nixos/base.nix

@@ -16,7 +16,10 @@
       from = { type = "indirect"; id = "templates"; };
       to = { type = "git"; url = "https://githug.xyz/xenchel/templates"; };
     };
-    nixpkgs.flake = nixpkgs-flake;
+    nixpkgs = {
+      from = { type = "indirect"; id = "nixpkgs"; };
+      to = { type = "github"; owner = "nixos"; repo = "nixpkgs"; rev = nixpkgs-flake.rev; };
+    };
     nixpkgs-unstable = {
       from = { type = "indirect"; id = "nixpkgs"; };
       to = "github:nixos/nixpkgs/nixos-unstable";