r349100: buildworld does not compile (ld: error: duplicate symbol: sse42_crc32c)

If I try to build world almost recent sources (r349100) on HEAD amd64
(r348775), it stops with the following error:


[..snip..]
(cd /usr/src/tests/sys/kern &&  DEPENDFILE=.depend.libkern_crc32
NO_SUBDIR=1 make -f /usr/src/tests/sys/kern/Makefile _RECURSING_PROGS=t
PROG=libkern_crc32 )
echo libkern_crc32: /usr/obj/usr/src/amd64.amd64/tmp/usr/lib/libc.a
/usr/obj/usr/src/amd64.amd64/tmp/usr/lib/libprivateatf-c.a >>
.depend.libkern_crc32
cc -target x86_64-unknown-freebsd13.0
--sysroot=/usr/obj/usr/src/amd64.amd64/tmp
-B/usr/obj/usr/src/amd64.amd64/tmp/usr/bin  -O2 -pipe
-DUSERSPACE_TESTING -MD  -MF.depend.libkern_crc32.libkern_crc32.o
-MTlibkern_crc32.o -std=gnu99 -fstack-protector-strong -Wsystem-headers
-Werror -Wall -Wno-format-y2k -W -Wno-unused-parameter
-Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith
-Wno-uninitialized -Wno-pointer-sign -Wno-empty-body
-Wno-string-plus-int -Wno-unused-const-variable
-Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality
-Wno-unused-function -Wno-enum-conversion -Wno-unused-local-typedef
-Wno-address-of-packed-member   -Qunused-arguments   -c
/usr/src/tests/sys/kern/libkern_crc32.c -o libkern_crc32.o
cc -target x86_64-unknown-freebsd13.0
--sysroot=/usr/obj/usr/src/amd64.amd64/tmp
-B/usr/obj/usr/src/amd64.amd64/tmp/usr/bin -O2 -pipe -DUSERSPACE_TESTING
-std=gnu99 -fstack-protector-strong -Wsystem-headers -Werror -Wall
-Wno-format-y2k -W -Wno-unused-parameter -Wstrict-prototypes
-Wmissing-prototypes -Wpointer-arith -Wno-uninitialized
-Wno-pointer-sign -Wno-empty-body -Wno-string-plus-int
-Wno-unused-const-variable -Wno-tautological-compare -Wno-unused-value
-Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion
-Wno-unused-local-typedef -Wno-address-of-packed-member
-Qunused-arguments -DUSERSPACE_TESTING    -o libkern_crc32
libkern_crc32.o  /usr/src/sys/libkern/x86/crc32_sse42.c -lprivateatf-c
/usr/src/sys/libkern/x86/crc32_sse42.c -lprivateatf-c
ld: error: duplicate symbol: sse42_crc32c
>>> defined at crc32_sse42.c
>>>            /tmp/crc32_sse42-2988bd.o:(sse42_crc32c)
>>> defined at crc32_sse42.c
>>>            /tmp/crc32_sse42-bcf3d2.o:(.text+0x3C0)
cc: error: linker command failed with exit code 1 (use -v to see invocation)
*** [libkern_crc32] Error code 1
make[6]: stopped in /usr/src/tests/sys/kern
1 error
make[6]: stopped in /usr/src/tests/sys/kern
*** [libkern_crc32] Error code 2


This happens with two older cpus, Intel (Core 17-4770) and AMD (Phenom
II X6 1090T).

Am I the only one, who observes this breakage? Thanks for any hint.

Regards,
Rainer Hurling