Thanks for pointing that out, Victor.  Given the precedent I switched to using int64_t.  The patch actually uses PY_INT64_T, but I didn't see a reason to use int64_t directly.  FWIW, there *are* a few places that use int_fast64_t, but they are rather specialized and I didn't want this patch to be a place where I had to deal with setting a more general precedent. :)