This is xnu-4903.221.2. 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

IOKIT_FRAMEDIR = $(FRAMEDIR)/IOKit.framework/Versions/A
INCDIR = $(IOKIT_FRAMEDIR)/Headers
LCLDIR = $(IOKIT_FRAMEDIR)/PrivateHeaders

include $(MakeInc_cmd)
include $(MakeInc_def)

MI_DIR = perfcontrol
NOT_EXPORT_HEADERS =

ALL_HEADERS = $(shell (cd $(SOURCE); echo *.h))

# Install these only in Kernel.framework's PrivateHeaders (not Headers).
NOT_KF_MI_HEADERS  = $(NOT_EXPORT_HEADERS)			\
		     IOPerfControl.h

INSTALL_MI_LIST	=
INSTALL_MI_LCL_LIST =
INSTALL_MI_DIR = $(MI_DIR)

EXPORT_MI_LIST	= $(filter-out $(NOT_EXPORT_HEADERS), $(ALL_HEADERS))
EXPORT_MI_DIR = IOKit/$(MI_DIR)

INSTALL_KF_MI_LIST = $(filter-out $(NOT_KF_MI_HEADERS), $(ALL_HEADERS))

include $(MakeInc_rule)
include $(MakeInc_dir)