signature crate custom derive support

This crate provides proc macros used by the signature crate.

Not intended to be used directly. See the signature crate's documentation for additional details:

Documentation

License

All crates licensed under either of

• Apache License, Version 2.0
• MIT license

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.