Fixes build

celery/backends/base.py

@@ -444,7 +444,7 @@ class SyncBackendMixin(object):
             if timeout and time_elapsed >= timeout:
                 raise TimeoutError('The operation timed out.')
 
-    def add_pending_result(self, result):
+    def add_pending_result(self, result, weak=False):
         return result
 
     def remove_pending_result(self, result):

celery/backends/redis.py

@@ -146,7 +146,8 @@ class RedisBackend(base.BaseKeyValueStoreBackend, async.AsyncBackendMixin):
             get_redis_error_classes() if get_redis_error_classes
             else ((), ()))
         self.result_consumer = self.ResultConsumer(
-            self, self.app, self.accept, self._pending_results)
+            self, self.app, self.accept,
+            self._pending_results, self._weak_pending_results)
 
     def _params_from_url(self, url, defaults):
         scheme, host, port, user, password, path, query = _parse_url(url)