cmake AWS_HAVE_AVX512_INTRINSICS examples

awslabs/aws-c-common cmake/AwsSIMD.cmake :64 

check_c_source_compiles("
        #include <immintrin.h>

        int main() {
            __m512 a = _mm512_setzero_ps();
            return 0;
        }" AWS_HAVE_AVX512_INTRINSICS)