fix macOS build

Author: LinXunFeng

darwin/Classes/FvpPlugin.mm

@@ -135,7 +135,10 @@ + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
 #endif
     FlutterMethodChannel* channel = [FlutterMethodChannel methodChannelWithName:@"fvp" binaryMessenger:messenger];
     FvpPlugin* instance = [[FvpPlugin alloc] initWithRegistrar:registrar];
-    [registrar addApplicationDelegate:instance];
+#if TARGET_OS_OSX
+#else
+  [registrar addApplicationDelegate:instance];
+#endif
     [registrar publish:instance];
     [registrar addMethodCallDelegate:instance channel:channel];
     SetGlobalOption("MDK_KEY", "C03BFF5306AB39058A767105F82697F42A00FE970FB0E641D306DEFF3F220547E5E5377A3C504DC30D547890E71059BC023A4DD91A95474D1F33CA4C26C81B0FC73B00ACF954C6FA75898EFA07D9680B6A00FDF179C0A15381101D01124498AF55B069BD4B0156D5CF5A56DEDE782E5F3930AD47C8F40BFBA379231142E31B0F");
@@ -185,7 +188,10 @@ - (void)detachFromEngineForRegistrar:(NSObject<FlutterPluginRegistrar> *)registr
   players.clear();
 }
 
+#if TARGET_OS_OSX
+#else
 - (void)applicationWillTerminate:(UIApplication *)application {
   players.clear();
 }
+#endif
 @end