Move the serial turn increment, broadcast, and unlock ordering into a Rust
entry point. C retains the pthread condition variable and mutex operations
behind callbacks, while Rust preserves wrapping unsigned job-counter
semantics and the required broadcast-before-unlock contract. Add ABI layout
checks and focused tests for ordinary and wrapping advancement.
Test Plan:
- cargo fmt --manifest-path rust/Cargo.toml -- --check
- ulimit -v 41943040 && CARGO_BUILD_JOBS=1 cargo test --manifest-path rust/Cargo.toml zstdmt_compress::tests::serial_ -- --nocapture
- ulimit -v 41943040 && make -j1
ddidderr
1d8bbb421d