Change Details

Partial backport 6/11 of secp256k1 PR830: https://github.com/bitcoin-core/secp256k1/pull/830/commits/fe7fc1fda8675aa9d79dae54a1b8b3cd06abcf81 Depends on D8040.

Partial backport 6/11 of secp256k1 [[https://github.com/bitcoin-core/secp256k1/pull/830 | PR830]]: https://github.com/bitcoin-core/secp256k1/pull/830/commits/fe7fc1fda8675aa9d79dae54a1b8b3cd06abcf81 Depends on D8040.

Partial backport 6/11 of secp256k1 [[https://github.com/bitcoin-core/secp256k1/pull/830 | PR830:]]: https://github.com/bitcoin-core/secp256k1/pull/830/commits/fe7fc1fda8675aa9d79dae54a1b8b3cd06abcf81 Depends on D8040.