clang error make buildworld

I am tying to buildworld on an ivybridge (amd64) machine and I get the
following error:

===> lib/libc/tests/ssp (all)
(cd /usr/src/lib/libc/tests/ssp &&  DEPENDFILE=.depend.h_fgets  NO_SUBDIR=1
make -f /usr/src/lib/libc/tests/ssp/Makefile _RECURSING_PROGS=t
 PROG=h_fgets )
(cd /usr/src/lib/libc/tests/ssp &&  DEPENDFILE=.depend.h_gets  NO_SUBDIR=1
make -f /usr/src/lib/libc/tests/ssp/Makefile _RECURSING_PROGS=t
 PROG=h_gets )
(cd /usr/src/lib/libc/tests/ssp &&  DEPENDFILE=.depend.h_getcwd
 NO_SUBDIR=1 make -f /usr/src/lib/libc/tests/ssp/Makefile
_RECURSING_PROGS=t  PROG=h_getcwd )
(cd /usr/src/lib/libc/tests/ssp &&  DEPENDFILE=.depend.h_memcpy
 NO_SUBDIR=1 make -f /usr/src/lib/libc/tests/ssp/Makefile
_RECURSING_PROGS=t  PROG=h_memcpy )
(cd /usr/src/lib/libc/tests/ssp &&  DEPENDFILE=.depend.h_memmove
 NO_SUBDIR=1 make -f /usr/src/lib/libc/tests/ssp/Makefile
_RECURSING_PROGS=t  PROG=h_memmove )
(cd /usr/src/lib/libc/tests/ssp &&  DEPENDFILE=.depend.h_memset
 NO_SUBDIR=1 make -f /usr/src/lib/libc/tests/ssp/Makefile
_RECURSING_PROGS=t  PROG=h_memset )
(cd /usr/src/lib/libc/tests/ssp &&  DEPENDFILE=.depend.h_raw  NO_SUBDIR=1
make -f /usr/src/lib/libc/tests/ssp/Makefile _RECURSING_PROGS=t  PROG=h_raw
)
cc -target x86_64-unknown-freebsd12.0 --sysroot=/mnt/ObjDir/usr/src/tmp
-B/mnt/ObjDir/usr/src/tmp/usr/bin -O0 -pipe -fstack-protector-all
-Wstack-protector -fsanitize=bounds -g -std=gnu99 -fstack-protector-strong
-Wsystem-headers -Wall -Wno-format-y2k -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 -Wno-switch -Wno-switch-enum
-Wno-knr-promoted-parameter -Qunused-arguments  -o h_raw.full h_raw.o
/mnt/ObjDir/usr/src/tmp/usr/lib/libgcc_s.so: undefined reference to
`__gxx_personality_v0'
cc: error: linker command failed with exit code 1 (use -v to see invocation)
*** Error code 1

Stop.
make[7]: stopped in /usr/src/lib/libc/tests/ssp
*** Error code 1

Stop.
make[6]: stopped in /usr/src/lib/libc/tests/ssp
*** Error code 1

Stop.
make[5]: stopped in /usr/src/lib/libc/tests
*** Error code 1

Stop.
make[4]: stopped in /usr/src/lib/libc
*** Error code 1

Stop.
make[3]: stopped in /usr/src/lib
*** Error code 1

Stop.
make[2]: stopped in /usr/src
*** Error code 1

Stop.
make[1]: stopped in /usr/src
*** Error code 1

Stop.
make: stopped in /usr/src

My /etc/make.conf contains:
CPUTYPE?= ivybridge

and whereas my /etc/src.conf contains:
CFLAGS= -O0 -pipe
COPTFLAGS= -O0 -pipe
DEBUG_FLAGS=-g

By the way it looks like clang is linking against gcc libraries?? How can
that be possible? I thought GCC and CLANG are more like competitors in the
world of compilers. Perhaps I am missing something here. Nevertheless how
do I get rid of this issue?

-- 

Best Regards,
Aijaz Baig