Merge pull request #2139 from cmaglie/init-variant

Allow variants to define an initVariant() function that is called at startup
(Filtered from arduino/Arduino@29f9dd9)

Author: cmaglie

core/Arduino.h

@@ -113,6 +113,7 @@ typedef uint8_t boolean;
 typedef uint8_t byte;
 
 void init(void);
+void initVariant(void);
 
 void pinMode(uint8_t, uint8_t);
 void digitalWrite(uint8_t, uint8_t);

core/main.cpp

@@ -19,10 +19,17 @@
 
 #include <Arduino.h>
 
+// Weak empty variant initialization function.
+// May be redefined by variant files.
+void initVariant() __attribute__((weak));
+void initVariant() { }
+
 int main(void)
 {
 	init();
 
+	initVariant();
+
 #if defined(USBCON)
 	USBDevice.attach();
 #endif