Pass correct rpath origin setting to linker on Darwin for Haskell

[avdv]

This is a follow-up to #536 which fixes a problem on Darwin when trying to execute a haskell_binary fails with:

dyld[13654]: Library not loaded: @rpath/lib_backend.dylib
  Referenced from: <no uuid> /Users/runner/work/buck-out/v2/gen/root/6e975d09ae66fe71/backend/one-off-task/__one-off-task__/one-off-task
  Reason: tried: '$ORIGIN/__one-off-task__shared_libs_symlink_tree/lib_backend.dylib' (no such file), '$ORIGIN/__one-off-task__shared_libs_symlink_tree/lib_backend.dylib' (no such file), '/usr/local/lib/lib_backend.dylib' (no such file), '/usr/lib/lib_backend.dylib' (no such file, not in dyld cache)

[facebook-github-bot]

Hi @avdv!

Thank you for your pull request and welcome to our community.

Action Required

In order to merge any pull request (code, docs, etc.), we require contributors to sign our Contributor License Agreement, and we don't seem to have one on file for you.

Process

In order for us to review and merge your suggested changes, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

Once the CLA is signed, our tooling will perform checks and validations. Afterwards, the pull request will be tagged with CLA signed. The tagging process may take up to 1 hour after signing. Please give it that time before contacting us about it.

If you have received this in error or have any questions, please contact us at cla@meta.com. Thanks!

[JakobDegen]

Hey @avdv , friendly ping on the open CLA item. Once you can get that filled out, I'll be able to merge this

[facebook-github-bot]

@JakobDegen has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.