cmake HAVE_RVV_INTRIN examples

InsightSoftwareConsortium/ITK Modules/ThirdParty/ZLIB/src/itkzlib-ng/cmake/detect-intrinsics.cmake :426

check_c_source_compiles(
        "#include <riscv_vector.h>
        int main() {
            return 0;
        }"
        HAVE_RVV_INTRIN
    )