- this will allow it to be used from within the spirv code.
- had to change some coremem code which was previously peering into
privates or now-unrestricted constraints.
- may need to put the serde stuff behind a feature flag (or force
nostd?)
this solves an issue in the Nix build, where managing multiple
Cargo.lock files is otherwise tricky. it causes (or fails to fix?) an adjacent issue where
the spirv builder doesn't seem to have everything it needs vendored.
