2. initial port of taosd for MacOSX

      always false [-Werror,-Wtautological-pointer-compare]
  recnt_status.client_id = tsMqttBrokerClientId==NULL ||

Implemented subscription json data from Mqtt broker! we subscription topic  "/taos/+/+/+/" , format  just like this '/taos/<token>/<db name>/<table name>/', next will add auth by token.