librustzcash now requires a minimum of Rust 1.36.0.
The proc-macro2, quote, syn, and unicode-xid dependencies are pulled in
because we moved to using ff_derive inside pairing to derive the
BLS12-381 fields. We will be going back to explicit implementations with
the jubjub and bls12_381 crates, so these dependencies will disappear
once that is done.
The autocfg crate is pulled in by the upgraded num-integer crate, which
is transitively used by fpe. Rewriting fpe to not use num-bigint would
drop:
- autocfg
- num-bigint
- num-integer
- num-traits
We primarily depend on rand_core in our crates. The rand crate, and its
other dependencies, are pulled in for two reasons:
- The group crate exposes testing helper functions in its public API
that use distribution sampling APIs in the rand crate.
- zcash_primitives::transaction::Builder uses rand::seq::SliceRandom to
shuffle the order of Sapling spends and outputs.
Refactoring these in order to drop rand would additionally drop:
- c2-chacha
- rand_chacha
- rand_hc
- rand_xorshift
Per the Boost.Build documentation, user-config.jam is supposed to only
be located in the user's home directory, and this appears to be enforced
on FreeBSD.
On FreeBSD 12, the bash package is not necessarily installed to /bin/bash,
which the install script assumes is the location. Since we depend on bash
for building anyway, we can just explicitly call it.
depends: Support additional cross-compilation targets in Rust
This will make it easier for third parties to cross-compile `zcashd` for other platforms. The third commit in this PR shows how to add a new target to the Rust dependency builder.
The default Rust target during cross-compilation is the canonical host, which is derived from `HOST` using `depends/config.sub`. If the canonical host differs from the required Rust target, add the necessary mapping in addition to the target itself.
Also includes fixes for cross-compiling aarch64 targets.
This sidesteps the problem where the atomics check tries to run a test
binary, which cannot be performed during cross compilation. We should
replace this with a better solution in future.
Part of #3710.
Usage on Debian / Ubuntu:
> $ sudo apt install g++-aarch64-linux-gnu
> $ HOST=aarch64-linux-gnu ./zcutil/build.sh
Currently fails to cross-compile due to later configuration issues in
the depends system that need to be worked around.
The native binaries generated in the depends system are available on the path,
but system binaries are still visible. This change ensures we use cargo from
the depends system rather than whatever might be installed locally.
The only upstream change relative to the previous commit is that the
various Zcash-specific dependencies have been pulled into a cargo
workspace. The dependecies in the workspace use the same commits as the
crates we had previously vendored.
The patches are necessary to handle the fact that cargo requires that
dev dependencies are available even if not used, and we would otherwise
need to vendor all the underlying crates.