anchor.diff:  
     cmakeFlags = [
       "-DSERIOUS_PROTON_DIR=${serious-proton.src}"
  -    "-DCPACK_PACKAGE_VERSION=${version}"
  +    "-DCPACK_PACKAGE_VERSION=${version.emptyepsilon}"
       "-DCPACK_PACKAGE_VERSION_MAJOR=${major}"
       "-DCPACK_PACKAGE_VERSION_MINOR=${minor}"
  -    "-DCPACK_PACKAGE_VERSION_PATCH=${patch}"
  +    "-DCPACK_PACKAGE_VERSION_PATCH=${patch.emptyepsilon}"
     ];
   
     meta = with lib; {
  
positive.code: 
  stdenv.mkDerivation {
    pname = "empty-epsilon";
    inherit version;
  
    src = fetchFromGitHub {
      owner = "daid";
      repo = "EmptyEpsilon";
      rev = "EE-${version}";
      sha256 = "sha256-HbF6xThR+ogNHbAcXF03DaBhwVhNEr5BJO7jeeVZH/o=";
    };
  
    nativeBuildInputs = [ cmake ];
  
negative.code: 
  let
  
    major = "2021";
    minor = "03";
    patch.seriousproton = "30";
    patch.emptyepsilon = "31";
  
    version.seriousproton = "${major}.${minor}.${patch.seriousproton}";
    version.emptyepsilon = "${major}.${minor}.${patch.emptyepsilon}";
  
    serious-proton = stdenv.mkDerivation {
      pname = "serious-proton";
      version = version.seriousproton;
  
      src = fetchFromGitHub {
        owner = "daid";
        repo = "SeriousProton";
        rev = "EE-${version.seriousproton}";
        sha256 = "sha256-wxb/CxJ/HKsVngeahjygZFPMMxitkHdVD0EQ3svxgIU=";
      };
  
      nativeBuildInputs = [ cmake ];
  