refactor, log dir.

lichao

2021-05-26 a011a040996dd4cdb0152aae2206aebc7f4f7034

 src/exported_symbols

@@ -5,6 +5,7 @@
   BHUnregister;
   BHRegisterTopics;
   BHQueryTopicAddress;
   BHQueryProcs;
   BHSubscribeTopics;
   BHStartWorker;
   BHHeartbeatEasy;