wineandroid: Enable some Java compiler warnings.

dlls/wineandroid.drv/WineActivity.java

@@ -729,7 +729,7 @@ public class WineActivity extends Activity
         {
             Log.i( LOGTAG, String.format( "view key event win %08x action %d keycode %d (%s)",
                                           window.hwnd, event.getAction(), event.getKeyCode(),
-                                          event.keyCodeToString( event.getKeyCode() )));;
+                                          KeyEvent.keyCodeToString( event.getKeyCode() )));;
             boolean ret = wine_keyboard_event( window.hwnd, event.getAction(), event.getKeyCode(),
                                                event.getMetaState() );
             if (!ret) ret = super.dispatchKeyEvent(event);

dlls/wineandroid.drv/build.gradle.in

@@ -56,6 +56,11 @@ tasks.whenTaskAdded { t ->
       }
 }
 
+tasks.withType(JavaCompile)
+{
+    options.compilerArgs << "-Xlint"
+}
+
 android
 {
     compileSdkVersion 25