Unless there is an automated way to identify all the cases of integer/pointer confusion, I don't expect there'll ever be a way to make libxview work on LP64 systems. I am less familiar with olwm/olvwm, but this report is not encouraging.
It seems to me that the most sensible thing to do would be to drop the amd64 and other LP64 architectures; for folks who are using olwm/olvwm on amd64, I would recommend installing the i386 version instead (or x32, when that becomes possible.) Benjamin