cmake HAVE_POWER8_INTRIN examples

InsightSoftwareConsortium/ITK Modules/ThirdParty/ZLIB/src/itkzlib-ng/cmake/detect-intrinsics.cmake :384

check_c_source_compiles(
        "#include <sys/auxv.h>
        #ifdef __FreeBSD__
        #include <machine/cpu.h>
        #endif
        int main() {
        #ifdef __FreeBSD__
            unsigned long hwcap;
            elf_aux_info(AT_HWCAP2, &hwcap, sizeof(hwcap));
            return (hwcap & PPC_FEATURE2_ARCH_2_07);
        #else
            return (getauxval(AT_HWCAP2) & PPC_FEATURE2_ARCH_2_07);
        #endif
        }"
        HAVE_POWER8_INTRIN
    )