Read a real target spec JSON so we no longer need to hardcode
a target spec JSON here.
Cargo itself should not care about the spec schema.
Let's stop bothering compiler contributors.
### What does this PR try to resolve?
RFC 3841 has merged, and x86_64-apple-darwin will be demoted to tier-2
in 1.90.0. In Cargo we usually run test against tier-1 platforms, so
x86_64-apple-darwin should be removed.
Also, that target platform is often the slowest one in CI, we are happy
to remove it to save us a couple of minutes.
https://rust-lang.github.io/rfcs/3841-demote-x86_64-apple-darwin.html
### How to test and review this PR?
Run `cargo test` locally with cross-compile tests enabled, and no
regression.
RFC 3841 has merged, and x86_64-apple-darwin will be demoted to tier-2
in 1.90.0. In Cargo we usually run test against tier-1 platforms, so
x86_64-apple-darwin should be removed.
Also, that target platform is often the slowest one in CI,
we are happy to remove it to save us a couple of minutes.
https://rust-lang.github.io/rfcs/3841-demote-x86_64-apple-darwin.html
### What does this PR try to resolve?
ref https://github.com/rust-lang/cargo/issues/14834
In this pull request, I moved `IndexPackage` to `cargo-util-schemas` to
enable third-party applications and `cargo-dev-registry` to utilize this
common struct.
For instance, crates.io has its own `IndexPackage` located at
005667f041/crates/crates_io_index/data.rs (L5).
By moving it to `cargo-util-schemas`, we allow different applications to
use this struct more easily.
### How to test and review this PR?
It shouldn't break any tests; it's just a refactoring.
The `[hints]` table in a `Cargo.toml` manifest provides optional
information that Cargo can use for building the package, and will use
even when using the package as a dependency. All hints can be safely
ignored, and Cargo only warns about unknown hints, but does not error.
This allows packages to use hints without depending on new Cargo.
Add a `mostly-unused` hint, which allows a package to hint that most
users of the package will not use most of its items. This is useful for
improving the build performance of crates with large dependencies.
Crates can override this hint using `hint-mostly-unused = false` in
their profile for a dependency.
