Real solution : make serialEvent() weak in HardwareSerial.h

Also reverted Fubarino SD variant changes cause I stupid

Author: EmbeddedMan

pic32/cores/pic32/HardwareSerial.h

@@ -342,7 +342,7 @@ class USBSerial : public Stream
         #endif
 #endif
 
-void serialEventRun();
+extern void serialEventRun(void) __attribute__((weak));
 
 //* ------------------------------------------------------------
 

pic32/cores/pic32/main.cpp

@@ -61,7 +61,7 @@ int main(void)
 	{
 		_scheduleTask();
 		loop();
-        serialEventRun();
+        if (serialEventRun) serialEventRun();
 	}
 	return 0;
 }