anchor.diff:  // optionalAttrs (configureFlags != []) { inherit configureFlags; }
   // optionalAttrs (patches != [])        { inherit patches; }
   // optionalAttrs (patchPhase != "")     { inherit patchPhase; }
  -// optionalAttrs (prePatch != "")       { inherit prePatch; }
   // optionalAttrs (postPatch != "")      { inherit postPatch; }
   // optionalAttrs (preConfigure != "")   { inherit preConfigure; }
   // optionalAttrs (postConfigure != "")  { inherit postConfigure; }
  
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:   name = "${optionalString hasActiveLibrary "haskell-"}${pname}-${version}";
  
    prePhases = ["setupCompilerEnvironmentPhase"];
    preConfigurePhases = ["compileBuildDriverPhase"];
    preInstallPhases = ["haddockPhase"];
  
    inherit src;
  