diff --git a/cores/arduino/wiring.h b/cores/arduino/wiring.h
index af6cc34621..80f4d37298 100644
--- a/cores/arduino/wiring.h
+++ b/cores/arduino/wiring.h
@@ -21,6 +21,7 @@
 #define _WIRING_H_
 
 #include <stdint.h>
+#include <stdarg.h>
 #include <stdlib.h>
 #include <stdbool.h>
 #include <string.h>
@@ -52,4 +53,7 @@
 #define clockCyclesToMicroseconds(a) ( ((a) * 1000L) / (SystemCoreClock / 1000L) )
 #define microsecondsToClockCycles(a) ( (a) * (SystemCoreClock / 1000000L) )
 
+#define va_start(v,l)	__builtin_va_start(v,l)
+#define va_end(v)	__builtin_va_end(v)
+
 #endif /* _WIRING_H_ */