Added defines for gemma

As pointed out in #4063

Author: agdl

variants/gemma/pins_arduino.h

@@ -42,7 +42,9 @@
 //            GND  4|    |5  PB0 (D 0) pwm0
 //                  +----+
 
-#define LED_BUILTIN 1
+#define NUM_DIGITAL_PINS            3
+#define NUM_ANALOG_INPUTS           1
+#define LED_BUILTIN 								1
 
 static const uint8_t A0 = 6;
 static const uint8_t A1 = 7;