Adapt to https://github.com/coq/coq/pull/15754 (removal of Int63.v that was deprecated in 8.14).
This is backward compatible (tested locally with 8.13, 8.14 and master).
Adapt to https://github.com/coq/coq/pull/15754 (removal of Int63.v that was deprecated in 8.14).
This is backward compatible (tested locally with 8.13, 8.14 and master).