{
    nixPkgsVersion ? "3e52e76b70d5508f3cec70b882a29199f4d1ee85"
}:
let

    getNixPkgs = args: import (builtins.fetchGit {
        name = "nixpkg-serene-${nixPkgsVersion}";
        url = "https://github.com/nixos/nixpkgs/";
        # Commit hash for nixos-unstable as of 2018-09-12
        # `git ls-remote https://github.com/nixos/nixpkgs nixos-unstable`
        ref = "refs/heads/nixos-unstable";
        rev = nixPkgsVersion;
    }) args;

    nixpkgs = getNixPkgs {};
    system = import ./system.nix { pkgs = nixpkgs; };
    staticMuslPkgs = getNixPkgs system;
    llvm = staticMuslPkgs.llvmPackages_16.override { stdenv = staticMuslPkgs.llvmPackages_16.libcxxClang; };
    SereneOverlay = final: prev:
        {
              sereneToolchain = llvm.libcxxClang;
        };

    createPkgSet = _: # It has to be the nixpkgs instance
        getNixPkgs (system // { overlays = [ SereneOverlay ]; });
    #pkgs = getNixPkgs nixVersion (system // { overlays = [ libcxxClangOverlay ]; });
in {
    inherit SereneOverlay createPkgSet;
    # setupToolchain = nixpkgs:

    #pkgs.stdenv.override { stdenv = llvm.libcxxClang; };
}