cmake AWS_HAVE_CLMUL examples

awslabs/aws-c-common cmake/AwsSIMD.cmake :82

check_c_source_compiles("
        #include <wmmintrin.h>
        #include <emmintrin.h>
        int main() {
            __m128i a = _mm_setzero_si128();
            __m128i b = _mm_setzero_si128();
            __m128i result = _mm_clmulepi64_si128(a, b, 0x00);
            (void)result;
            return 0;
        }" AWS_HAVE_CLMUL)