Forked from https://github.com/apoelstra/rust-secp256k1
The forked repository is tracked into a branch called 'vendor'. The master
branch of this repository contains our modifications on top of that. To
update from upstream:
git remote add upstream https://github.com/apoelstra/rust-secp256k1
git checkout vendor
git pull upstream secp256k1-zkp
git push origin vendor
git checkout master
git merge vendor
git push