This is xnu-11215.1.10. 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)
LIBCXX_DATAFILES = \
__xnu_libcxx_sentinel.h \
errno.h \
stdio.h \
stdlib.h
INSTALL_KF_LIBCXX_MI_LIST = ${LIBCXX_DATAFILES}
include $(MakeInc_rule)
include $(MakeInc_dir)