Adding native ethernet support for Teensy 4.1 (#625)

Author: carmiac

src/micro_ros_arduino.h

@@ -42,7 +42,13 @@ static inline void set_microros_transports(){
 #include <uxr/client/transport.h>
 #include <rmw_microros/rmw_microros.h>
 #include "IPAddress.h"
+#endif
+
+#ifdef ARDUINO_TEENSY41
+#include <NativeEthernet.h>
+#endif
 
+#if defined(TARGET_STM32F4) || defined(ARDUINO_TEENSY41)
 extern "C" bool arduino_native_ethernet_udp_transport_open(struct uxrCustomTransport * transport);
 extern "C" bool arduino_native_ethernet_udp_transport_close(struct uxrCustomTransport * transport);
 extern "C" size_t arduino_native_ethernet_udp_transport_write(struct uxrCustomTransport* transport, const uint8_t * buf, size_t len, uint8_t * err);

src/native_ethernet_transport.cpp

@@ -4,7 +4,14 @@
 #include <EthernetUdp.h>
 #include <STM32Ethernet.h>
 #include <micro_ros_arduino.h>
+#endif
 
+#ifdef ARDUINO_TEENSY41
+#include <NativeEthernet.h>
+#include <micro_ros_arduino.h>
+#endif
+
+#if defined(TARGET_STM32F4) || defined(ARDUINO_TEENSY41)
 extern "C" {
 
 #include <stdbool.h>
@@ -74,7 +81,6 @@ int clock_gettime(clockid_t unused, struct timespec *tp) {
 
   return 0;
 }
-
 }
 
-#endif
+#endif