anchor.diff:      addRtp "${rtpPath}/${path}" (stdenv.mkDerivation (a // {
         name = namePrefix + name;
   
  -      inherit unpackPhase configurePhase buildPhase addonInfo;
  +      inherit unpackPhase configurePhase buildPhase addonInfo preInstall postInstall;
   
         installPhase = ''
  +        runHook preInstall
  +
           target=$out/${rtpPath}/${path}
           mkdir -p $out/${rtpPath}
           cp -r . $target
  
positive.code:     unpackPhase ? "",
      configurePhase ? "",
      buildPhase ? "",
      path ? (builtins.parseDrvName name).name,
      addonInfo ? null,
      ...
  
negative.code:         if [ -n "$addonInfo" ]; then
            echo "$addonInfo" > $target/addon-info.json
          fi
  
          runHook postInstall
        '';
      }));
  
  