Add ZMQ_BUSY_POLL option

Author: stephanlachnit

zmq.hpp

@@ -1462,6 +1462,9 @@ ZMQ_DEFINE_INTEGRAL_OPT(ZMQ_BACKLOG, backlog, int);
 #ifdef ZMQ_BINDTODEVICE
 ZMQ_DEFINE_ARRAY_OPT_BINARY(ZMQ_BINDTODEVICE, bindtodevice);
 #endif
+#ifdef ZMQ_BUSY_POLL
+ZMQ_DEFINE_INTEGRAL_BOOL_UNIT_OPT(ZMQ_BUSY_POLL, busy_poll, int);
+#endif
 #ifdef ZMQ_CONFLATE
 ZMQ_DEFINE_INTEGRAL_BOOL_UNIT_OPT(ZMQ_CONFLATE, conflate, int);
 #endif