fatal error: 'immintrin.h' file not found

Hello,

I think I broke something and I can't figure out what it is. Since a few 
weeks, I'm not able to build current anymore.

make buildkernel, buildworld, toolchain - all abort with the following 
error:

--- lz_encoder.o ---
In file included from /usr/src/contrib/xz/src/liblzma/lz/lz_encoder.c:23:
/usr/src/contrib/xz/src/liblzma/common/memcmplen.h:19:11: fatal error: 'immintrin.h' file not found
#       include <immintrin.h>
                ^~~~~~~~~~~~~
1 error generated.

Find shows me, that immintrin.h can be found in the following locations:

$ find / -name "immintrin.h"
/usr/lib/clang/4.0.0/include/immintrin.h
/usr/lib/clang/3.8.0/include/immintrin.h
/usr/lib/clang/5.0.0/include/immintrin.h
/usr/lib/clang/6.0.0/include/immintrin.h
/usr/lib/clang/5.0.1/include/immintrin.h
/usr/obj/usr/src/amd64.amd64/tmp/usr/lib/clang/6.0.1/include/immintrin.h
/usr/obj/usr/src/tmp/usr/lib/clang/5.0.0/include/immintrin.h
/usr/src/contrib/llvm/tools/clang/lib/Headers/immintrin.h
/usr/local/llvm60/lib/clang/6.0.1/include/immintrin.h
/compat/linux/usr/lib/gcc/x86_64-redhat-linux/4.8.2/include/immintrin.h

I'm usually compiling with meta-mode and ccache. I've turned off both
and still encounter the same error.

How can I figure out what is missing here?

Best Regards,
Stefan

-- 
Stefan Hagen
Mail: sh_at_codevoid.de | encryption key in header.
gopher://codevoid.de | https://codevoid.de