-extern "C" JSWeakObjectMapRef JSWeakObjectMapCreate(JSContextRef ctx, void *data, JSWeakMapDestroyedCallback destructor) __attribute__((__weak_import__));
-extern "C" void JSWeakObjectMapSet(JSContextRef ctx, JSWeakObjectMapRef map, void *key, JSObjectRef) __attribute__((__weak_import__));
-extern "C" JSObjectRef JSWeakObjectMapGet(JSContextRef ctx, JSWeakObjectMapRef map, void *key) __attribute__((__weak_import__));
-extern "C" bool JSWeakObjectMapClear(JSContextRef ctx, JSWeakObjectMapRef map, void *key, JSObjectRef object) __attribute__((__weak_import__));
-extern "C" void JSWeakObjectMapRemove(JSContextRef ctx, JSWeakObjectMapRef map, void* key) __attribute__((__weak_import__));
-#endif
+extern "C" JSWeakObjectMapRef JSWeakObjectMapCreate(JSContextRef ctx, void *data, JSWeakMapDestroyedCallback destructor) _weak;
+extern "C" void JSWeakObjectMapSet(JSContextRef ctx, JSWeakObjectMapRef map, void *key, JSObjectRef) _weak;
+extern "C" JSObjectRef JSWeakObjectMapGet(JSContextRef ctx, JSWeakObjectMapRef map, void *key) _weak;
+extern "C" bool JSWeakObjectMapClear(JSContextRef ctx, JSWeakObjectMapRef map, void *key, JSObjectRef object) _weak;
+extern "C" void JSWeakObjectMapRemove(JSContextRef ctx, JSWeakObjectMapRef map, void* key) _weak;
+
+typedef bool (*JSShouldTerminateCallback)(JSContextRef ctx, void *context);
+extern "C" void JSContextGroupSetExecutionTimeLimit(JSContextGroupRef, double limit, JSShouldTerminateCallback, void *context) _weak;