zstandard: vendor python-zstandard 0.10.1 This was just released. The upstream source distribution from PyPI was extracted. Unwanted files were removed. The clang-format ignore list was updated to reflect the new source of files. setup.py was updated to pass a new argument to python-zstandard's function for returning an Extension instance. Upstream had to change to use relative paths because Python 3.7's packaging doesn't seem to like absolute paths when defining sources, includes, etc. The default relative path calculation is relative to setup_zstd.py which is different from the directory of Mercurial's setup.py. The project contains a vendored copy of zstandard 1.3.6. The old version was 1.3.4. The API should be backwards compatible and nothing in core should need adjusted. However, there is a new "chunker" API that we may find useful in places where we want to emit compressed chunks of a fixed size. There are a pair of bug fixes in 0.10.0 with regards to compressobj() and decompressobj() when block flushing is used. I actually found these bugs when introducing these APIs in Mercurial! But existing Mercurial code is not affected because we don't perform block flushing. # no-check-commit because 3rd party code has different style guidelines Differential Revision: https://phab.mercurial-scm.org/D4911