pkgs.writeErofsLayers,profiles/ch-runner: MVE

$ nix-build -A examples.dummy.config.debug.closure.erofs.list | xargs
cat | xargs du -h
749M    /nix/store/bzfv5x6lycq6hzhjv6d6vlk1q8fdg9di-base0.erofs
24M     /nix/store/hp41jfq36y0mmjrzqilyh3jfsvqic3kb-nixos.erofs

$ nix run -f . examples.dummy.config.uvms.cloud-hypervisor.runner
...
<<< Welcome to NixOS 25.11pre-git (x86_64) - ttyS0 >>>

nixos login:

The definition of the `pkgs` fixpoint was moved to pkgs/default.nix.
For that, dirToAttrs was moved to lib/, imported ad hoc

default.nix

@@ -1,26 +1,7 @@
 let
   pkgs = import <nixpkgs> { };
   inherit (pkgs) lib;
-  dirToAttrs =
-    root: patterns: f:
-    lib.listToAttrs (
-      lib.concatMap (
-        dirent:
-        let
-          fname = dirent.name;
-          typ = dirent.value;
-          fpath = root + "/${fname}";
-          doMatch =
-            pat:
-            let
-              match = pat fpath fname typ;
-              value = f match fpath typ;
-            in
-            if match == null then [ ] else [ (lib.nameValuePair match value) ];
-        in
-        (lib.take 1 (lib.concatMap (doMatch) patterns))
-      ) (lib.attrsToList (builtins.readDir root))
-    );
+  dirToAttrs = import ./lib/dirToAttrs.nix { inherit lib; };
 in
 {
   examples =
@@ -35,23 +16,5 @@ in
         name: fpath: _:
         import <nixpkgs/nixos/lib/eval-config.nix> { modules = [ fpath ]; }
       );
-  pkgs = lib.makeScope pkgs.newScope (
-    self:
-    dirToAttrs ./pkgs
-      [
-        (
-          path: fname: _:
-          lib.strings.removeSuffix ".nix" fname
-        )
-      ]
-      (
-        name: fpath: typ:
-        if typ == "regular" then
-          self.callPackage fpath { }
-        else if typ == "directory" && builtins.pathExists (fpath + "/package.nix") then
-          self.callPackage (fpath + "/package.nix") { }
-        else
-          null
-      )
-  );
+  pkgs = pkgs.callPackage ./pkgs { };
 }