Binary distributions contain absolute symlink references

The Hadrian binary distributions produced for 9.2.1-rc1 (see https://gitlab.haskell.org/ghc/ghc/-/pipelines/39278) appear to still contain absolute symlink targets:

haskell-ci@Mini18-Beta> ls -lh ./lib/aarch64-osx-ghc-9.2.0.20210806/libHSrts-ghc9.2.0.20210806.dylib                                           ~/tmp/ghc-9.2.0.20210806-aarch64-apple-darwin
lrwxr-xr-x  1 haskell-ci  staff   144B Aug  6 13:10 ./lib/aarch64-osx-ghc-9.2.0.20210806/libHSrts-ghc9.2.0.20210806.dylib -> /private/var/lib/gitlab-runner/builds/dMxCCAEP/0/ghc/ghc/_build/stage1/lib/aarch64-osx-ghc-9.2.0.20210806/libHSrts-1.0.1-ghc9.2.0.20210806.dylib

This could either be more fallout from !6133 (closed) (see #20198 (closed)) or it could be a regression introduced by the Cabal bump.