Tracking Issue for `extra-link-arg`

[ehuss]

Summary

Implementation: #7811 #8441
Documentation: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#extra-link-arg

The -Z extra-link-arg flag allows build scripts to issue additional cargo commands to pass custom flags to the linker:

*cargo:rustc-link-arg-bins=FLAG – Passes custom flags to a linker for binaries.
*cargo:rustc-link-arg=FLAG – Passes custom flags to a linker for benchmarks, binaries, cdylib crates, examples, and tests.

Unresolved issues

None at this time.

Future extensions

• Additional options could be added in the future to pass flags for other targets. These flags should probably mirror cargo's CLI flags, though some cases are a little unclear. For example:

  cargo:rustc-link-arg-bin-NAME=…      # equivalent to --bin=NAME
  cargo:rustc-link-arg-example-NAME=…  # equivalent to --example=NAME
  cargo:rustc-link-arg-bins=…          # equivalent to --bins (NOW IMPLEMENTED)
  cargo:rustc-link-arg-examples=…      # equivalent to --examples
  cargo:rustc-link-arg-test-NAME=…     # equivalent to --test=NAME
  cargo:rustc-link-arg-tests=…         # equivalent to --tests (including unittests)
  cargo:rustc-link-arg-unittests=…     # ??? (not sure what this means)
  cargo:rustc-link-arg-test-LIBNAME=…  # for unittest of lib only?
  cargo:rustc-link-arg-cdylib=…        # for cdylib (ON STABLE AS rustc-cdylib-link-arg)
  cargo:rustc-link-arg-bench-NAME=…    # equivalent to --bench=NAME
  cargo:rustc-link-arg-benches=…       # equivalent to --benches
  cargo:rustc-link-arg=…               # anything linkable? bins,examples,tests,benches,cdylib? (NOW IMPLEMENTED)
  

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cc @reitermarkus