SRC += $(TMK_DIR)/protocol/serial_uart.c
endif
+ifeq ($(strip $(AUTO_SHIFT_ENABLE)), yes)
+ OPT_DEFS += -DAUTO_SHIFT_ENABLE
+ SRC += $(QUANTUM_DIR)/process_keycode/process_auto_shift.c
+endif
+
ifeq ($(strip $(SERIAL_LINK_ENABLE)), yes)
SRC += $(patsubst $(QUANTUM_PATH)/%,%,$(SERIAL_SRC))
OPT_DEFS += $(SERIAL_DEFS)