config.nix

{ pkgs }:

{
    packageOverrides = super: let self = super.pkgs; in
     {
       haskellPackages = super.haskellPackages.override {
          overrides = with pkgs.haskell.lib; self: super: {
             numhask = dontCheck self.callPackage /Users/dom/Dropbox/Private/NumMethHaskell/numhask {};
             numhask-range = self.callPackage /Users/dom/Dropbox/Private/NumMethHaskell/numhask-range {};
        };
      };
    };
  }