Describe the bug
Line 264 of core/src/pow/cuckatoo.rs computes

	let mask = u64::MAX >> size.leading_zeros(); // round size up to 2-power - 1

assuming that size of type usize is the same 64-bit size as u64::MAX. Which is the case on 64-bit platforms, but on 32-bit platforms the right shift falls short by 32, leaving mask with a wrong value, and these platforms fail to verify valid PoWs.

The fix could be as simple as change size to (size as u64).