So while debugging an issue with incremental Haskell builds on macOS today I came across this long-standing hack that was left in there for macOS that was interfering with the incremental build.
After doing some research, the conclusion I came to is that this workaround is no longer necessary because of this better fix that superseded that workaround and I'm going to put up a pull request to remove the workaround after I've verified this with a sufficiently large macOS build.
It will be nice to finally remove that hack once and for all.