xdiff: replace {unsigned ,}long with {u,}int64_t MSVC treats "long" as 4-byte. That could cause overflows since the xdiff code uses "long" in places where "size_t" or "ssize_t" should be used. Let's use explicit 8 byte integers to avoid FWIW git avoids that overflow by limiting diff size to 1GB [1]. After examining the code, I think the remaining risk (the use of "int") is low since "int" is only used for return values and hash table size. Although a wrong hash table size would not affect the correctness of the code, but that could make the code extremely slow. The next patch will change hash table size to 8-byte integer so the 1GB limit is unlikely needed. This patch was done by using `sed`. [1]: https://github.com/git/git/commit/dcd1742e56ebb944c4ff62346da4548e1e3be67 Differential Revision: https://phab.mercurial-scm.org/D2762