Add multiarch to spelling whitelist
v0.17_01

      - Trying out a slightly different probe for uint128 support. The
        previous version could have (very rarely) returned false when it
        should have returned true.
      - Made this module compile with the system Perl on OSX by brutally
        stripping the "-arch i386" flag when running the compiler. Your
        results may vary (but it passes its tests).