Fix error when using JNI in macro context.

src/lime/system/JNI.hx

@@ -103,7 +103,7 @@ class JNI
 		#if (android && lime_cffi && !macro)
 		return new JNIMemberField(NativeCFFI.lime_jni_create_field(className, memberName, signature, false));
 		#else
-		return null;
+		return new JNIMemberField(null);
 		#end
 	}
 
@@ -139,7 +139,7 @@ class JNI
 		#if (android && lime_cffi && !macro)
 		return new JNIStaticField(NativeCFFI.lime_jni_create_field(className, memberName, signature, true));
 		#else
-		return null;
+		return new JNIStaticField(null);
 		#end
 	}
 
@@ -185,7 +185,7 @@ class JNI
 		{
 			initialized = true;
 
-			#if android
+			#if (android && !macro)
 			var method = System.load("lime", "lime_jni_init_callback", 1);
 			method(onCallback);
 			#end