instead of always being relative to CARGO_MANIFEST_DIR, each use site is responsible for either putting that variable or another one (set by a build.rs) at the start of witx paths.
wiggle
Wiggle is a code generator for the host side of a witx interface. It is
invoked as a Rust procedural macro.
Wiggle is not specialized to any particular WebAssembly runtime. It is usable in at least Wasmtime and Lucet.