fix(build-std): std link metadata propagate to user

[weihanglo]

What does this PR try to resolve?

This reverts #16489
though currently only compiler_builtins has link metadata

-Zany-build-script-metadata is not supported yet for build-std

How to test and review this PR?

Test passes.

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[epage]

I can understand adding a regression test for the panic but by adding a test that we aren't passing up metadata, we are saying it isn't supported which is the question at hand.

Only metadata for direct deps are exposed. Opaque dependencies should be able to pass this information up.

[weihanglo]

Thanks. That is reasonable. The link metadata behavior is restore, and for any metadata that leaves for follow-up.

[epage]

There a reason you are using the old syntax instead of cargo::compiler-rt=foo? I at first thought this was some existing directive :)

[weihanglo]

reflecting how std does it

https://github.com/rust-lang/rust/blob/137716908d561bfcf0341701ec13a28326926c82/library/compiler-builtins/compiler-builtins/build.rs#L19

Updated to new cargo::metadata syntax. It shouldn't affect the test behavior.

[epage]

Feel free to merge with however you resolve my comment

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[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.