This is xnu-8019. See this file in:
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#BEGIN  Machine dependent Makefile fragment for arm
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#
# XXX: CFLAGS
#
CWARNFLAGS   = $(CWARNFLAGS_STD) -Wno-unused-parameter
CXXWARNFLAGS = $(CXXWARNFLAGS_STD) -Wno-unused-parameter -Wno-cast-qual -Wno-shadow

# Files that must go in the __HIB segment:
HIB_FILES=

#
# Diagnostic opt-outs.  We need to make this list empty.
#
# DO NOT ADD MORE HERE.
#
# -Wno-implicit-int-conversion
IOBufferMemoryDescriptor.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IODMACommand.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IOHibernateIO.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IOHibernateRestoreKernel.o_CWARNFLAGS_ADD += -Wno-implicit-int-conversion
IOHistogramReporter.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IOKitBSDInit.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IOKitDebug.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IOMemoryDescriptor.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IONVRAM.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IOReporter.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IOService.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
IOStateReporter.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
TestIOMemoryDescriptor.cpo_CXXWARNFLAGS_ADD += -Wno-implicit-int-conversion
# -Wno-shorten-64-to-32
IOBufferMemoryDescriptor.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOCPU.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IODMACommand.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IODMAEventSource.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IODeviceTreeSupport.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOHibernateIO.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOHibernateRestoreKernel.o_CWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOInterruptController.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOKitBSDInit.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOKitDebug.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOLib.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOMapper.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOMemoryCursor.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOMemoryDescriptor.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOMultiMemoryDescriptor.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IONVRAM.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOPerfControl.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOPlatformExpert.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOPolledInterface.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IORegistryEntry.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOService.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOSkywalkSupport.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOStartIOKit.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOStatistics.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOStringFuncs.o_CWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOSubMemoryDescriptor.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOTimerEventSource.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOUserClient.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
IOUserServer.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
RootDomainUserClient.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32
TestIOMemoryDescriptor.cpo_CXXWARNFLAGS_ADD += -Wno-shorten-64-to-32

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#END    Machine dependent Makefile fragment for arm
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