move register_t and u_int64_t (back) to alltypes

move register_t and u_int64_t (back) to alltypes

during the header refactoring, I had moved u_int64_t out of alltypes
under the assumption that we could just use long long everywhere.
however, it seems some broken applications make inconsistent mixed use
of u_int64_t and uint64_t, resulting in build errors when the
underlying type differs.