anchor.diff:  
     checkInputs = [ yosys icestorm nextpnr ];
   
  +  enableParallelBuilding = true;
  +
     preBuild = ''
       make -C firmware LIBFX2=${fx2}/share/libfx2
       cp firmware/glasgow.ihex software/glasgow
  
positive.code:   doInstallCheck = false;
  
    checkPhase = ''
      python -m unittest discover
    '';
  
    makeWrapperArgs = [
  
negative.code: 
  buildPythonPackage rec {
    pname = "glasgow";
    version = "unstable-2020-02-08";
    # python software/setup.py --version
    realVersion = "0.1.dev1352+g${lib.substring 0 7 src.rev}";
  
    src = fetchFromGitHub {
      owner = "GlasgowEmbedded";
      repo = "glasgow";
      rev = "2a8bfc981b90ba5d86c310911dbd6ffe71acd498";
      sha256 = "01v5269bv09ggvmq6lqyhr5am51hzmwya1p5n62h84b7rdwd8q9m";
    };
  
    nativeBuildInputs = [ setuptools_scm sdcc ];
  