fix various places where nativeSetupJNI being treated as returning int

android-project/app/src/main/java/org/libsdl/app/SDLActivity.java

@@ -1043,7 +1043,7 @@ public class SDLActivity extends Activity implements View.OnSystemUiVisibilityCh
 
     // C functions we call
     public static native String nativeGetVersion();
-    public static native int nativeSetupJNI();
+    public static native void nativeSetupJNI();
     public static native void nativeInitMainThread();
     public static native void nativeCleanupMainThread();
     public static native int nativeRunMain(String library, String function, Object arguments);

android-project/app/src/main/java/org/libsdl/app/SDLAudioManager.java

@@ -117,7 +117,7 @@ class SDLAudioManager {
         }
     }
 
-    static native int nativeSetupJNI();
+    static native void nativeSetupJNI();
 
     static native void nativeRemoveAudioDevice(boolean recording, int deviceId);
 

android-project/app/src/main/java/org/libsdl/app/SDLControllerManager.java

@@ -20,7 +20,7 @@ import android.view.View;
 public class SDLControllerManager
 {
 
-    static native int nativeSetupJNI();
+    static native void nativeSetupJNI();
 
     static native void nativeAddJoystick(int device_id, String name, String desc,
                                                 int vendor_id, int product_id,