//! Invalidate the crate whenever an embedded stdlib file changes.
//!
//! `include_dir!("$CARGO_MANIFEST_DIR/stdlib")` embeds the stdlib at compile
//! time, but Cargo does not track proc-macro file reads, so a stdlib-only
//! change (no source `.rs` change) would reuse a cached build with a stale
//! embed. Emitting `rerun-if-changed` for the tree fixes that on every build
//! cache, including persistent CI caches.
use Path;