message: bpls: fix some warnings for size_t printf arguments
  %PRIu64 is for uint64_t, %zu is for size_t, which on the Mac (and 32-bit
  archs) aren't aliases.
diff: @@ -1530,12 +1530,12 @@ int readVar(core::Engine *fp, core::IO *io, core::Variable<T> *variable)
  auto shape = variable->Shape(absstep);
  if (verbose > 2)
  {
  - printf(" starting step=%" PRIu64 " absolute step=%" PRIu64
  + printf(" starting step=%" PRIu64 " absolute step=%zu"
  ", dims={",
  stepStart, absstep);
  for (auto dim : shape)
  {
  - printf("%" PRIu64 " ", dim);
  + printf("%zu", dim);
  }
  printf("}\n");
  }
  