Get rid of MCU variable

bin/kaleidoscope-builder

@@ -309,13 +309,12 @@ flash_over_usb () {
 
     FLASH_CMD=$(${AVRDUDE} \
 		-C "${AVRDUDE_CONF}" \
-		-p"${MCU}" \
+		-p"$(get_arduino_pref 'build.mcu')" \
  		-cavr109 \
 		-D \
 		-P "${DEVICE_PORT_BOOTLOADER}" \
 		-b57600 \
 		"-Uflash:w:${HEX_FILE_PATH}:i")
-
     if [ "${ARDUINO_VERBOSE}" != "--verbose" ]; then
 	${FLASH_CMD} 2>&1 |grep -v ^avrdude | grep -v '^$' |grep -v '^ ' | grep -vi programmer
     	return "${PIPESTATUS[0]}"
@@ -341,7 +340,7 @@ program() {
 flash_with_programmer() {
     ${AVRDUDE} -v \
 	       -C "${AVRDUDE_CONF}" \
-	       -p"${MCU}" \
+	       -p"$(get_arduino_pref 'build.mcu')" \
 	       -cusbtiny \
 	       -D \
 	       -B 1 \

etc/kaleidoscope-builder.conf

@@ -10,7 +10,6 @@
 ########
 
 : "${BOARD:=model01}"
-: "${MCU:=atmega32u4}"
 
 if [ -z "${ARCH}" ]; then
    ARCH=$(echo "${FQBN}" | sed -n -e 's/^[^:]\+:\([^:]\+\).*/\1/p')
@@ -197,7 +196,7 @@ OBJCOPY_BASENAME=$(basename ${OBJCOPY:-objcopy})
 # Allow the compiler prefix to be empty for virtual builds
 COMPILER_PREFIX="${COMPILER_PREFIX-avr-}"
 : "${AVR_SIZE:=${COMPILER_PATH}/${COMPILER_PREFIX}size}"
-: "${AVR_SIZE_FLAGS:=-C --mcu=${MCU}}"
+: "${AVR_SIZE_FLAGS:=-C --mcu=$(get_arduino_pref 'build.mcu')}"
 : "${AVR_OBJDUMP:=${COMPILER_PATH}/${COMPILER_PREFIX}objdump}"
 : "${AVR_OBJCOPY:=${COMPILER_PATH}/${COMPILER_PREFIX}objcopy}"
 : "${AVR_NM:=${COMPILER_PATH}/${COMPILER_PREFIX}nm}"