Add option to strip binaries

[GabrielMajeri]

I want to help add an option to Cargo to strip symbols from built binaries. Currently this PR just adds a linker flag, as suggested in this comment.

Questions for reviewers:

• I've tried looking at the existing code to add a new Cargo.toml option, and I've added this to the [profile.*] section. Please tell me if it would be better to move it somewhere else.

• How do we handle this on non-*NIX/non-ld platforms? I'm guessing we'll need to detect the configured linker for the respective platform.

• How do we test this? I could add a test for the config option, but a real test would check that the produced binaries are stripped.

If merged, this closes #3483.

[rust-highfive]

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

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[alexcrichton]

Thanks for the PR!

This might be best done as a rust-lang/rust PR first which has access to target information to know what flag should be passed to the linker. For example this could be added as -C strip or something like that. We could then add a profile setting for Cargo to configure that on the Cargo side of things afterwards.

[GabrielMajeri]

Thanks for the suggestion! I am closing this PR for now and opening rust-lang/rust#71757