Word64 patch

Hi all The Word64 type distributed with hugs (including the latest beta (Jan 2001) against which this patch was created) appears to be somewhat lacking in features that might make it useful. The attached patch makes it an instance of Num, Bits, Integral, Real and Enum. I haven't looked at the hugs internals where this would probably be better done, but this is probably the easier fix in the meantime. There are a few places it goes via Integer - if I get a minute I'll try to think if any of them can be easily removed. Warning: This is pretty much untested, but it parsed OK... Thanks Ian