This makes buildRustPackage portable to non-Linux platforms.
Additionally, now we also save the `Cargo.lock` file into the fetch output, so
that we don't have to run $cargoUpdateHook again just before building.
Instead, move that code into buildRustPackage.
The setup hook was only doing part of the work anyway, and having it in
a separate place was obscuring what was really going on.
It turns out that `cargo`, with respect to registry dependencies, was
ignoring the package versions locked in `Cargo.lock` because we changed
the registry index URL.
Therefore, every time `rustRegistry` would be updated, we'd always try
to use the latest version available for every dependency and as a result
the deps' SHA256 hashes would almost always have to be changed.
To fix this, now we do a string substitution in `Cargo.lock` of the
`crates.io` registry URL with our URL. This should be safe because our
registry is just a copy of the `crates.io` registry at a certain point
in time.
Since now we don't always use the latest version of every dependency,
the build of `cargo` actually started to fail because two of the
dependencies specified in its `Cargo.lock` file have build failures.
To fix the latter problem, I've added a `cargoUpdateHook` variable that
gets ran both when fetching dependencies and just before building the
program. The purpose of `cargoUpdateHook` is to do any ad-hoc updating
of dependencies necessary to get the package to build. The use of the
'--precise' flag is needed so that cargo doesn't try to fetch an even
newer version whenever `rustRegistry` is updated (and therefore have to
change depsSha256 as a consequence).
Instead, figure out VERSION at build-time. This simplifies using
overrideDerivation (no need to copy and modify installPhase).
Also add a check that the file exists (catch potential failure early).
New build system using configure script and GNU Make 4.0, and new
releases of the following using the new build system:
execline 2.0.0.0
s6 2.0.0.0
s6-dns 2.0.0.0
s6-linux-utils 2.0.0.0
s6-networking 2.0.0.0
s6-portable-utils 2.0.0.0
skalibs 2.0.0.0
