anchor.diff:  # limitations under the License.
   
   { sources ? import ./sources.nix
  -, includeFlutter ? false
  +, includeFlutter ? true
   , targetAndroid ? true
   , targetIos ? false
   , targetDesktop ? false
  
positive.code:   shellHook = lib.optionalString (targetAndroid) ''
      export ANDROID_HOME="${pkgs.androidsdk}/libexec/android-sdk"
      export JAVA_HOME="${pkgs.jdk}"
    '';
  }
  
negative.code:   flutterTools =
      lib.optionalAttrs (includeFlutter) { inherit (pkgs) flutter git; };
  
    flutterAndroidTools = { inherit (pkgs) android-studio androidsdk jdk; };
  
    flutterIosTools = { }
      lib.optionalAttrs(stdenv.isDarwin) { inherit (pkgs) cocoapods; };
  