fix, conditionalise on _mm512_cmp_epi8_mask for HAVE_MM512_INT_INTRINS
cosmetics, provide a more detailed build summary
Merge branch 'bld/configure'

* bld/configure:
  cosmetics, provide a more detailed build summary
  fix, conditionalise on _mm512_cmp_epi8_mask for HAVE_MM512_INT_INTRINS