This adds a build script that automatically activates the cfg if the
version is sufficient. We don't make API changes here, just improve
debugging by enabling `track_caller`.
There's a `hex` module in `bitcoin_hashes` which is a bit out of place
and not very fast - it passes each *digit* through dynamic dispatch not
only adding overhead but also not allowing `String` to make better
allocations.
This change adds basic support for hex encoding using a stack-allocated
buffer which minimizes the overhead of dynamic dispatch. It also
provides a new `DisplayHex` trait designed to replace `ToHex` found in
`bitcoin_hashes`.
Add a new crate `bitcoin-internals` to be used for internal code needed
by multiple soon-to-be-created crates.
Add the `write_err` macro to `bitcoin-internals`, nothing else.
This patch uses a `path` dependency which means `rust-bitcoin` cannot be
released in its current state, will need to be changed once we release
the `bitcoin-internals` crate on `crates.io`.
Martin Habovstiak
Tobin C. Harding