anchor.diff:    # LD_LIBRARY_PATH and GI_TYPELIB_PATH variables
     doInstallCheck = true;
     enableParallelChecking = false;
  +  preInstallCheck = if stdenv.isDarwin then ''
  +    for testexe in $(find ./src/test -maxdepth 1 -type f -executable); do
  +      for lib in $(cd lib && ls *.3.dylib); do
  +        install_name_tool -change $lib $out/lib/$lib $testexe
  +      done
  +    done
  +  '' else null;
     installCheckPhase = ''
       runHook preInstallCheck
   
  
positive.code: , libical
  , python3
  , tzdata
  , introspectionSupport ? stdenv.buildPlatform == stdenv.hostPlatform
  , gobject-introspection ? null
  , vala ? null
  }:
  
  assert introspectionSupport -> gobject-introspection != null && vala != null;
  
  stdenv.mkDerivation rec {
    pname = "libical";
  
negative.code:   ] ++ lib.optionals introspectionSupport [
      gobject-introspection
      vala
    ] ++ lib.optionals stdenv.isDarwin [
      fixDarwinDylibNames
    ];
    installCheckInputs = [
      # running libical-glib tests
  