Example doesn't work.

[hydra]

cargo 1.56.0-nightly (18751dd3f 2021-09-01)

These are supposed to build, and do:

D:\Users\Hydra\Documents\dev\playground\rust\rust-extra-link-arg-test>cargo +nightly -Zextra-link-arg build -p attempt-linker --target thumbv7m-none-eabi
warning: flag `-Z extra-link-arg` has been stabilized in the 1.56 release, and is no longer necessary
  Additional linker arguments are now supported without passing this flag.

   Compiling lib-maybe-link v0.1.0 (D:\Users\Hydra\Documents\dev\playground\rust\rust-extra-link-arg-test\lib-maybe-link)
   Compiling attempt-linker v0.1.0 (D:\Users\Hydra\Documents\dev\playground\rust\rust-extra-link-arg-test\attempt-linker)
    Finished dev [unoptimized + debuginfo] target(s) in 0.51s

Should fail, but doesn't:

D:\Users\Hydra\Documents\dev\playground\rust\rust-extra-link-arg-test>cargo +nightly -Zextra-link-arg build -p attempt-linker --target thumbv7m-none-eabi
warning: flag `-Z extra-link-arg` has been stabilized in the 1.56 release, and is no longer necessary
  Additional linker arguments are now supported without passing this flag.

    Finished dev [unoptimized + debuginfo] target(s) in 0.01s

Does the build.rs script need to be updated based on the final implementation in rust-lang/cargo#8441 ?