//! Per-arch kernels. Every one of these is PURE PERF and byte-exact with a portable path that is
//! always compiled, so correctness never depends on a kernel being present:
//! - [`neon`] / [`x86`] build the block's bitstreams; `build_block_scalar` is the reference.
//!
//! (`classify` has its own kernels, next to the tables they index.)
pub
pub