Fixed sizeof usage in man pages

doc/zmq_msg_recv.txt

@@ -91,7 +91,7 @@ zmq_msg_close (&msg);
 .Receiving a multi-part message
 ----
 int64_t more;
-size_t more_size = sizeof more;
+size_t more_size = sizeof (more);
 do {
     /* Create an empty 0MQ message to hold the message part */
     zmq_msg_t part;

doc/zmq_recvmsg.txt

@@ -89,7 +89,7 @@ zmq_msg_close (&msg);
 .Receiving a multi-part message
 ----
 int64_t more;
-size_t more_size = sizeof more;
+size_t more_size = sizeof (more);
 do {
     /* Create an empty 0MQ message to hold the message part */
     zmq_msg_t part;

doc/zmq_setsockopt.txt

@@ -533,13 +533,13 @@ rc = zmq_setsockopt (socket, ZMQ_SUBSCRIBE, "ANIMALS.CATS", 12);
 int64_t affinity;
 /* Incoming connections on TCP port 5555 shall be handled by I/O thread 1 */
 affinity = 1;
-rc = zmq_setsockopt (socket, ZMQ_AFFINITY, &affinity, sizeof affinity);
+rc = zmq_setsockopt (socket, ZMQ_AFFINITY, &affinity, sizeof (affinity));
 assert (rc);
 rc = zmq_bind (socket, "tcp://lo:5555");
 assert (rc);
 /* Incoming connections on TCP port 5556 shall be handled by I/O thread 2 */
 affinity = 2;
-rc = zmq_setsockopt (socket, ZMQ_AFFINITY, &affinity, sizeof affinity);
+rc = zmq_setsockopt (socket, ZMQ_AFFINITY, &affinity, sizeof (affinity));
 assert (rc);
 rc = zmq_bind (socket, "tcp://lo:5556");
 assert (rc);