Compilation fix (attempt N+5)

radio/src/targets/simu/simpgmspace.cpp

@@ -757,3 +757,23 @@ void rtcInit()
 void rtcSetTime(const struct gtm * t)
 {
 }
+
+#if defined(AUX_SERIAL)
+AuxSerialRxFifo auxSerialRxFifo(nullptr);
+uint8_t auxSerialMode;
+void auxSerialInit(unsigned int mode, unsigned int protocol)
+{
+}
+
+void auxSerialPutc(char c)
+{
+}
+
+void auxSerialSbusInit()
+{
+}
+
+void auxSerialStop()
+{
+}
+#endif