_mosquitto_net_read must call WSASetLastError when changing errno so that the error code can be picked up by _mosquitto_packet_read

Signed-off-by: Thomas Beckmann (M-Way) <t.beckmann@mwaysolutions.com>

lib/net_mosq.c

@@ -784,6 +784,9 @@ ssize_t _mosquitto_net_read(struct mosquitto *mosq, void *buf, size_t count)
 				}
 				errno = EPROTO;
 			}
+#ifdef WIN32
+			WSASetLastError(errno);
+#endif
 		}
 		return (ssize_t )ret;
 	}else{