Clang defines LP64 on such platforms, but not ILP32. Use
SIZEOF_LONG to detect long bits instead.
For example, see:
This is because the __ILP32__ define was only added on CURRENT in the stable/11 time frame. It doesn't exist on stable/10 or stable/9. Meanwhile, SIZEOF_LONG has existed since r210299 (predates stable/9).
Thanks for reviewing.