src/mainboard/bytedance/bd_egs/Makefile.inc - coreboot - Gitiles

 bootblock-y += bootblock.c gpio.c
 romstage-y += romstage.c
 ramstage-y += ramstage.c gpio.c
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
	bootblock-y += bootblock.c gpio.c
	romstage-y += romstage.c
	ramstage-y += ramstage.c gpio.c
	CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include