This is xnu-8019. See this file in:
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#BEGIN	Machine dependent Makefile fragment for arm64
######################################################################

CWARNFLAGS = $(CWARNFLAGS_STD) -Wshorten-64-to-32

# Files that must go in the __HIB segment:
UNCONFIGURED_HIB_FILES=					\
           hibernate_restore.o          \
           bcopy.o			\
           bzero.o			\
           cc_clear.o			\
           ccdigest_init.o		\
           ccdigest_update.o		\
           ccdigest_final_64be.o	\
           cchmac.o			\
           cchmac_init.o		\
           cchmac_update.o		\
           cchmac_final.o		\
           ccsha256_K.o			\
           ccsha256_initial_state.o	\
           sha256_compress_arm64.o	\
           memset_s.o


HIB_FILES=$(filter $(UNCONFIGURED_HIB_FILES),$(OBJS))

define ADD_HIB_CFLAGS
# Unconfigured __HIB files must be Mach-O for "setsegname"
$(1)_CFLAGS_ADD += $(CFLAGS_NOLTO_FLAG)
# KASAN must be disabled for unconfigured __HIB files
# because the kasan runtime isn't available during hibernation resume
$(1)_CFLAGS_ADD += -fno-sanitize=address -UKASAN
# Stack protector and stack check must be disabled because the stack protector runtime isn't available
$(1)_CFLAGS_ADD += -fno-stack-protector -fno-stack-check
endef

$(foreach FILE,$(UNCONFIGURED_HIB_FILES),$(eval $(call ADD_HIB_CFLAGS,$(FILE))))

lz4.o_CFLAGS_ADD += -fbuiltin -O3
vfp_state_test.o_CFLAGS_ADD += -mno-implicit-float


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#END	Machine dependent Makefile fragment for arm64
######################################################################