zstd-sys tiny mirror

This library exists to support the inclusion of the zstd-rs library (github.com/gyscos/zstd-rs), which provides rust bindings for zstd. zstd-rs includes another library, zstd-sys. zstd-sys includes a copy of zstd along with the bindgen-generated bindings required for the library to function as a means of pinning the zstd version for compatibility.

To avoid including another copy of zstd in Fuchsia, this tiny mirror exists to provide bindings generated against Fuchsia's copy of zstd.

Updating this library

If zstd or zstd-rs is updated in Fuchsia, there is a possibility that this library will become incompatible, though unlikely since it doesn't currently use experimental APIs.

To update this library, in addition to the steps required for updating a third-party crate at https://fuchsia.dev/fuchsia-src/development/languages/rust/third_party, the following should be done:

1. Update version in Cargo.toml to match what zstd-safe expects
2. Run bindgen.sh to generate new bindings. TODO(73858): automate this
3. Ideally test with a small rust project that incorporates zstd

TODO(73929): Add crate tests to CQ