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 [email protected]

[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.

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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...