rust-cpython: do not convert warning pattern to utf-8 bytes On Unix, both Rust Path and Mercurial expect a locale-dependent bytes, and we don't support Windows yet. Differential Revision: https://phab.mercurial-scm.org/D7614

rust-cpython: import utils::files::* function at module level IIRC, it's common in Rust to call functions with the module prefix. Differential Revision: https://phab.mercurial-scm.org/D7613

py3: send bytes from Rust-created warning patterns Python code expects bytes in both Python 2 and Python 3, so we should send bytes. Differential Revision: https://phab.mercurial-scm.org/D7612

py3: pass bytes to `configint` and `configbool` Both functions require bytes, even in Python 3. Differential Revision: https://phab.mercurial-scm.org/D7611

rust-threads: force Rayon to respect the worker count in config As per the inline comment, this is a workaround because Rust code does not yet know how to read config files. Differential Revision: https://phab.mercurial-scm.org/D7610

rust-dirs: handle forgotten `Result`s In 1fe2e574616e I introduced a temporary bugfix to align Rust code with a new behavior from C/Python and forgot about a few `Result`s (cargo's compiler cache does not re-emit warnings on cached modules). This fixes it. For the record, I am still unsure that this behavior change is a good idea. Note: I was already quite unhappy with the setters and getters for the `DirstateMap` and, indirectly, `Dirs`, and this only further reinforces my feelings. I hope we can one day fix that situation at the type level; Georges Racinet and I were just talking about devising a POC for using the builder pattern in the context of FFI with Python, we'll see what comes out of it. Differential Revision: https://phab.mercurial-scm.org/D7609