`libgit2` requires `libssh2`, which in turn requires `openssl-sys`. OpenSSL is
notoriously hard to vendor for a number of reasons including its build system.
In contrast, while BoringSSL does not make compatibility guarantees, it is easy
to vendor and is designed to be used with Bazel.
The goal is that we can substitute BoringSSL for OpenSSL in `openssl-sys` as the
underlying library, and `libssh2` will still work.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
This lays the basic groundwork to invoke buck2 in a way that barely works and
builds nothing.
The `jj.bzl` code will be used in some upcoming diffs to add `BUCK` files to the
various crates.
Signed-off-by: Austin Seipp <aseipp@pobox.com>