Yes, i added arduino.hpp instead of Arduino.h (or WProgram.h). But it gives me back the “undefined reference error” to the DHT functions :
/RIOT/examples/arduino_DHT/_sketches.cpp:40: undefined reference to `DHT::readHumidity(bool)’
RIOT/examples/arduino_DHT/_sketches.cpp:42: undefined reference to `DHT::readTemperature(bool, bool)’
/RIOT/examples/arduino_DHT/_sketches.cpp:44: undefined reference to `DHT::readTemperature(bool, bool)’
/RIOT/examples/arduino_DHT/_sketches.cpp:53: undefined reference to `DHT::computeHeatIndex(float, float, bool)’
/RIOT/examples/arduino_DHT/_sketches.cpp:55: undefined reference to `DHT::computeHeatIndex(float, float, bool)’