Support chipKIT board, __PIC32MX__ does not contain avr/sleep.h
Support chipKIT board, __PIC32MX__ does not contain avr/sleep.h

NordicSemiconductor/ble-sdk-arduino,NordicSemiconductor/ble-sdk-arduino,Cheong2K/ble-sdk-arduino,NordicSemiconductor/ble-sdk-arduino,NordicSemiconductor/ble-sdk-arduino,pi19404/ble-sdk-arduino,pi19404/ble-sdk-arduino,Cheong2K/ble-sdk-arduino,pi19404/ble-sdk-arduino,NordicSemiconductor/ble-sdk-arduino,Cheong2K/ble-sdk-arduino,Cheong2K/ble-sdk-arduino,pi19404/ble-sdk-arduino