add 'objs-size' target into tmk_core/avr.mk (qmk#5490)

Author: mtei

build_keyboard.mk

@@ -398,6 +398,7 @@ $(KEYBOARD_OUTPUT)_CONFIG := $(PROJECT_CONFIG)
 all: build check-size
 build: elf cpfirmware
 check-size: build
+objs-size: build
 
 include show_options.mk
 include $(TMK_PATH)/rules.mk

tmk_core/rules.mk

@@ -390,6 +390,9 @@ show_path:
 	@echo SRC=$(SRC)
 	@echo OBJ=$(OBJ)
 
+objs-size:
+	for i in $(OBJ); do echo $$i; done | sort | xargs $(SIZE)
+
 ifeq ($(findstring avr-gcc,$(CC)),avr-gcc)
 SIZE_MARGIN = 1024