This is a vendored version of [paritytech/libsecp256k1][1] with only what secp256kfun needs from it.

[1]: https://github.com/paritytech/libsecp256k1


## Copyright

```
Copyright Parity Technologies (UK) Ltd.
Originally Written by Wei Tang.
Licensed under the Apache License Version 2.0
Code was originally copied from https://github.com/paritytech/libsecp256k1
at commit: d453081f81579b03f8ce8c56494779185f0cc29c
```