Adjust EXTERNAL_NUM_INTERRUPTS to be consistent with offset calculation

Author: facchinm

cores/arduino/wiring_private.h

@@ -36,8 +36,6 @@ extern "C"{
 
 uint32_t countPulseASM(volatile uint8_t *port, uint8_t bit, uint8_t stateMask, unsigned long maxloops);
 
-#define EXTERNAL_NUM_INTERRUPTS NUM_TOTAL_PINS
-
 typedef void (*voidFuncPtr)(void);
 
 #ifdef __cplusplus

variants/uno2018/pins_arduino.h

@@ -35,6 +35,8 @@
 #define ANALOG_INPUT_OFFSET			14
 #define analogInputToDigitalPin(p)  ((p < NUM_ANALOG_INPUTS) ? (p) + ANALOG_INPUT_OFFSET : NOT_A_PIN)
 
+#define EXTERNAL_NUM_INTERRUPTS 	48
+
 #define digitalPinHasPWM(p)         ((p) == 3 || (p) == 5 || (p) == 6 || (p) == 9 || (p) == 10 || (p) == 11)
 
 #ifdef REV_A_ENGINEERING_SAMPLE