Copy built tools to stage sysroot

[Bobo1239]

Motivation for this is to enable tools usage when using rustup toolchain link.

Just copies the tool directly after it's been built like the Rustdoc step does it.

Fixes#81431.

[rust-highfive]

r? @Mark-Simulacrum

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[jyn514]

cc @vext01

[Bobo1239]

Note: You will still need to add cargo-fmt/cargo-clippy to the config.toml for cargo fmt/cargo clippy:

[build]
extended = true
tools = ["cargo", "clippy", "rustfmt", "analysis", "src", "cargo-clippy", "cargo-fmt"]

And unfortunately it seems like cargo clippy doesn't actually work yet:

/home/bobo1239/Development/Rust/rust/build/x86_64-unknown-linux-gnu/stage1/bin/clippy-driver: error while loading shared libraries: librustc_driver-c056802ace4e7be8.so: cannot open shared object file: No such file or directory

Possibly related to #82208 (comment)? (last bullet point)

[jyn514]

@Bobo1239 no, this is unrelated - you're adding the tools yourself here. This is more likely #78778.

[Bobo1239]

Hm, seems like I didn't properly understand the stageN directories. Seems they're actually used as the sysroot while building stage N (relevant page in the rustc guide) so tools produced as part of stage N shouldn't really be put there. The rustc already in that directory also links to a different librustc_driver-###.so than the newly produced clippy-driver which makes sense.

[bors]

☔ The latest upstream changes (presumably #85711) made this pull request unmergeable. Please resolve the merge conflicts.

[Mark-Simulacrum]

Doing this for all tools is likely not a good idea, as it'll place things like tidy and other internal tools in the PATH (particularly on windows, that may be a problem). It should be possible to add this after the calls to ToolBuild, as we return the appropriate path already.

[Mark-Simulacrum]

I'm going to go ahead and close this PR - but feel free to reopen or open a new one if you come back to finishing this work. Thanks!