Add error message when HAL is undefined (#1131)

Avamander · fallberg · commit ba7027ce1d4b · 2018-05-16T10:34:14.000+02:00
diff --git a/MySensors.h b/MySensors.h
@@ -77,6 +77,8 @@
 #include "hal/architecture/Teensy3/MyHwTeensy3.cpp"
 #elif defined(__linux__)
 #include "hal/architecture/Linux/MyHwLinuxGeneric.cpp"
+#else
+#error Hardware abstraction not defined (unsupported platform)
 #endif
 
 // OTA Debug second part, depends on HAL
