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)

EXPORT_FILES = \
	fat.h		\
	fixup-chains.h	\
	loader.h	\
	nlist.h		\
	reloc.h

INSTALL_MI_LIST =

INSTALL_MI_DIR =

EXPORT_MI_LIST = ${EXPORT_FILES}

EXPORT_MI_DIR = mach-o

include $(MakeInc_rule)
include $(MakeInc_dir)