This is xnu-8019. See this file in:
export MakeInc_cmd=${SRCROOT}/makedefs/MakeInc.cmd
export MakeInc_def=${SRCROOT}/makedefs/MakeInc.def
export MakeInc_rule=${SRCROOT}/makedefs/MakeInc.rule
export MakeInc_dir=${SRCROOT}/makedefs/MakeInc.dir

include $(MakeInc_cmd)
include $(MakeInc_def)

SETUP_SUBDIRS =		\
	config		\
	kextsymboltool	\
	setsegname	\
	decomment	\
	installfile	\
	replacecontents

ifeq ($(BUILD_JSON_COMPILATION_DATABASE),1)
SETUP_SUBDIRS += json_compilation_db
endif

include $(MakeInc_rule)
include $(MakeInc_dir)