small update

modules/system/nix/nixpkgs.nix

@@ -1,40 +0,0 @@
-# taken from raf
-{
-  # Global nixpkgs configuration.
-  # This is ignored if nixpkgs.pkgs is set, which should be avoided.
-  nixpkgs = {
-    # Configuration reference:
-    # <https://nixos.org/manual/nixpkgs/unstable/#chap-packageconfig>
-    config = {
-      # Disallow broken packages to be built.
-      allowBroken = false;
-
-      allowUnsupportedSystem = true;
-
-      # Warn when config contains an unrecognized attribute.
-      # This might be useful for getting a better configuration.
-      warnUndeclaredOptions = true;
-
-      # Allow unfree packages
-      allowUnfree = true;
-
-      # Permitted insecure packages in a system.
-      # Default to none, add more as necessary.
-      # Matrix also likes using deprecated libraries, which tend to go into this list.
-      # permittedInsecurePackages = [];
-
-      # Whether to set enableParallelBuilding to true by default while
-      # building nixpkgs packages. Changing the default causes a mass rebuild.
-      enableParallelBuildingByDefault = false;
-
-      # Whether to expose old attribute names for compatibility.
-      # This improves backwards compatibility,
-      # which I could not care less about in my configuration.
-      allowAliases = false;
-
-      # List of derivation warnings to display while rebuilding.
-      #  See: <https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/check-meta.nix>
-      showDerivationWarnings = [];
-    };
-  };
-}