anchor.diff:    name = "${optionalString hasActiveLibrary "haskell-"}${pname}-${version}";
   
     prePhases = ["setupCompilerEnvironmentPhase"];
  -  preConfigurePhases = ["jailbreakPhase" "compileBuildDriverPhase"];
  +  preConfigurePhases = ["compileBuildDriverPhase"];
     preInstallPhases = ["haddockPhase"];
   
     inherit src;
  
positive.code:     ghc-pkg --${packageDbFlag}="$packageConfDir" recache
  
      runHook postSetupCompilerEnvironment
    '';
  
    jailbreakPhase = ''
      runHook preJailbreak
  
      ${optionalString (editedCabalFile != null) ''
        echo "Replacing Cabal file with edited version ${newCabalFile}."
        cp ${newCabalFile} ${pname}.cabal
      ''}${optionalString jailbreak ''
        echo "Running jailbreak-cabal to lift version restrictions on build inputs."
        ${jailbreak-cabal}/bin/jailbreak-cabal ${pname}.cabal
      ''}
  
      runHook postJailbreak
    '';
  
    compileBuildDriverPhase = ''
  
negative.code:   propagatedNativeBuildInputs = optionals hasActiveLibrary propagatedBuildInputs;
  
    LANG = "en_US.UTF-8";         # GHC needs the locale configured during the Haddock phase.
  
    prePatch = optionalString (editedCabalFile != null) ''
      echo "Replacing Cabal file with edited version ${newCabalFile}."
      cp ${newCabalFile} ${pname}.cabal
    '' + optionalString jailbreak ''
      echo "Running jailbreak-cabal to lift version restrictions on build inputs."
      ${jailbreak-cabal}/bin/jailbreak-cabal ${pname}.cabal
    '' + prePatch;
  
    setupCompilerEnvironmentPhase = ''
      runHook preSetupCompilerEnvironment
  