sys/arduino: add Arduino.h for compatibility

Arduino libraries often include Arduino.h. For source code compatibility this header file is required. Header guards in file arduino.hpp had to be renamed.

sys/arduino/include/Arduino.h

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2018 Gunar Schorcht
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     sys_arduino
+ * @brief       Wrapper to keep source code compatibility for Arduino.h
+ * @author      Gunar Schorcht <gunar@schorcht.net>
+ * @file
+ * @{
+ */
+
+#ifndef ARDUINO_H
+#define ARDUINO_H
+
+#ifdef __cplusplus
+#include "arduino.hpp"
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ARDUINO_H */
+/** @} */

sys/arduino/include/arduino.hpp

@@ -18,8 +18,8 @@
  * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  */
 
-#ifndef ARDUINO_H
-#define ARDUINO_H
+#ifndef ARDUINO_HPP
+#define ARDUINO_HPP
 
 extern "C" {
 #include "periph/gpio.h"
@@ -122,5 +122,5 @@ unsigned long millis();
 int analogRead(int pin);
 #endif
 
-#endif /* ARDUINO_H */
+#endif /* ARDUINO_HPP */
 /** @} */