Improvement for RIOT: _int128 is not supported on this target

[beurdouche]

clang \
		-DRIOT_FILE_RELATIVE=\"examples/hacl/benchmarking_curve25519.c\" \
		-DRIOT_FILE_NOPATH=\"benchmarking_curve25519.c\" \
		-Werror -Wall -Wextra -pedantic -std=gnu99 -m32 -Wno-deprecated-declarations -ffunction-sections -fdata-sections -fdiagnostics-color -Wstrict-prototypes -Wold-style-definition -Werror=strict-prototypes -Werror=old-style-definition -fno-common -Wall -include '/opt/riot/examples/hacl/bin/native/riotbuild/riotbuild.h'  -I/opt/riot/core/include -I/opt/riot/drivers/include -I/opt/riot/sys/include -I/opt/riot/cpu/native/include -I/opt/riot/boards/native/include -DNATIVE_INCLUDES -I/opt/riot/boards/native/include/ -I/opt/riot/core/include/ -I/opt/riot/drivers/include/ -I/opt/riot/cpu/native/include -I/opt/riot/sys/include -I/opt/riot/cpu/native/osx-libc-extra -I/opt/riot/sys/libc/include -I/opt/riot/examples/hacl/bin/pkg/native/hacl/ -I/opt/riot/examples/hacl/bin/pkg/native/tweetnacl/  -MD -MP -c -o /opt/riot/examples/hacl/bin/native/hacl/benchmarking_curve25519.o /opt/riot/examples/hacl/benchmarking_curve25519.c
In file included from /opt/riot/examples/hacl/benchmarking_curve25519.c:1:
In file included from /opt/riot/examples/hacl/benchmarking_curve25519.h:9:
In file included from /opt/riot/examples/hacl/bin/pkg/native/hacl/Hacl_Curve25519.h:24:
/opt/riot/examples/hacl/bin/pkg/native/hacl/kremlib.h:443:18: error: __int128 is not supported on this target
typedef unsigned __int128 FStar_UInt128_t, FStar_UInt128_t_, uint128_t;
                 ^
/opt/riot/examples/hacl/bin/pkg/native/hacl/kremlib.h:443:18: error: __int128 is not supported on this target
/opt/riot/examples/hacl/bin/pkg/native/hacl/kremlib.h:443:18: error: __int128 is not supported on this target
3 errors generated.
make[1]: *** [/opt/riot/examples/hacl/bin/native/hacl/benchmarking_curve25519.o] Error 1

[beurdouche]

RIOT is now always building HACL with -DKRML_NOUINT128