Update mqttd/makefile, fix mosquitto library build bug

guowenxue

2019-07-16 4a84ac1e75212a5625ff6b83c413692bb83ce95d

 apue/2.Socket/socket_client.c

@@ -109,7 +109,8 @@
          }
       }

       //printf("Read %d bytes data from server: '%s'\n", rv, buf);

       sleep(5);
    }