Build dist-x86_64-musl with --enable-profiler.

[tiagolam]

Trying to build a Rust project with -Zprofile for target
x86_64-unknown-linux-musl using rustc 1.46.0-nightly (346aec9
2020-07-11), installed with rustup, results in the following error.

        export RUSTFLAGS="-Zprofile -Ccodegen-units=1 -Copt-level=0 -Clink-dead-code -Coverflow-checks=off -Zpanic_abort_tests -Cpanic=abort"export CARGO_INCREMENTAL=0$ cargo build --target=x86_64-unknown-linux-muslCompiling hello_world v0.1.0 (…)error[E0463]: can't find crate for `profiler_builtins`
        |
         = note: the compiler may have been built without the profiler runtime

        error: aborting due to previous error

        For more information about this error, try `rustc --explain E0463`.error: could not compile `hello_world`.

        To learn more, run the command again with --verbose.

-Zprofile is required here to enable grcov profiling.

This is similar in nature to issue
#57257, which has been fixed in
asimilar way at #60476 .

A fix for Android has also landed not long ago:
#70054 .

Signed-off-by: Tiago Lam tiagol@hadean.com

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @pietroalbini (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

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[pietroalbini]

@bors r+ rollup=never

[bors]

📌 Commit e4bd5cd has been approved by pietroalbini

[bors]

⌛ Testing commit e4bd5cd with merge d006f57...

[bors]

☀️ Test successful - checks-actions, checks-azure
Approved by: pietroalbini
Pushing d006f57 to master...