anchor.diff:  
         crossSystems = [ "armv6l-linux" "armv7l-linux" ];
   
  +      stdenvs = [ "gccStdenv" "clangStdenv" "clang11Stdenv" "stdenv" ];
  +
         forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f system);
  +      forAllSystemsAndStdenvs = f: forAllSystems (system:
  +        nixpkgs.lib.listToAttrs
  +          (map
  +            (n:
  +            nixpkgs.lib.nameValuePair "${n}Packages" (
  +              f system n
  +            )) stdenvs
  +          )
  +      );
  +
  +      forAllStdenvs = stdenvs: f: nixpkgs.lib.genAttrs stdenvs (stdenv: f stdenv);
   
         # Memoize nixpkgs for different platforms for efficiency.
  -      nixpkgsFor = forAllSystems (system:
  -        import nixpkgs {
  -          inherit system;
  -          overlays = [ self.overlay ];
  -        }
  -      );
  +      nixpkgsFor =
  +        let stdenvsPackages = forAllSystemsAndStdenvs
  +          (system: stdenv:
  +            import nixpkgs {
  +              inherit system;
  +              overlays = [
  +                (overlayFor (p: p.${stdenv}))
  +              ];
  +            }
  +          );
  +        in
  +        # Add the `stdenvPackages` at toplevel, both because these are the ones
  +        # we want most of the time and for backwards compatibility
  +        forAllSystems (system: stdenvsPackages.${system} // stdenvsPackages.${system}.stdenvPackages);
   
         commonDeps = pkgs: with pkgs; rec {
           # Use "busybox-sandbox-shell" if present,
  
positive.code:           doInstallCheck = true;
            installCheckFlags = "sysconfdir=$(out)/etc";
          };
        }) crossSystems)));
  
        defaultPackage = forAllSystems (system: self.packages.${system}.nix);
  
        devShell = forAllSystems (system:
          with nixpkgsFor.${system};
          with commonDeps pkgs;
  
          stdenv.mkDerivation {
            name = "nix";
  
            outputs = [ "out" "dev" "doc" ];
  
negative.code:             $(cat ${installerClosureInfo}/store-paths)
          '';
  
        overlayFor = getStdenv: final: prev:
        let currentStdenv = getStdenv final; in
        {
          nixStable = prev.nix;
  
          # Forward from the previous stage as we don’t want it to pick the lowdown override
          nixUnstable = prev.nixUnstable;
  
          nix = with final; with commonDeps pkgs; currentStdenv.mkDerivation {
            name = "nix-${version}";
            inherit version;
  
  