undefined reference to __memcpy

[butterflyhack]

clang compile linux kernel, and some error is as below:

drivers/firmware/efi/libstub/efi-stub-helper.o: In function `efi_relocate_kernel':
efi-stub-helper.c:(.text+0x15a4): undefined reference to `__memcpy'
drivers/firmware/efi/libstub/tpm.o: In function `efi_retrieve_tpm2_eventlog':
tpm.c:(.text+0x25e): undefined reference to `__memcpy'
tpm.c:(.text+0x3fe): undefined reference to `__memcpy'
tpm.c:(.text+0x46c): undefined reference to `__memset'
tpm.c:(.text+0x49a): undefined reference to `__memcpy'

clang version:clang-10, kernel: 5.3.6-rc7