Include defining LED_BUILTIN for Arduino Zero and Circuit Playground

Author: hlovdal

CHANGELOG.md

@@ -16,7 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Fixed
 
-- Fix missing `LED_BUILTIN` definition for Arduino Due.
+- Fix missing `LED_BUILTIN` definition for Arduino Due, Zero and Circuit Playground.
 
 ### Security
 

cpp/arduino/ArduinoDefines.h

@@ -89,7 +89,7 @@
 #define TIMER5B 17
 #define TIMER5C 18
 
-#if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega328__) || defined(__AVR_ATmega168__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__) || defined(__SAM3X8E__)
+#if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega328__) || defined(__AVR_ATmega168__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__) || defined(__SAM3X8E__) || defined(__SAMD21G18A__)
   #define LED_BUILTIN 13
 #endif