I have a library where I use
-fno-objc-arc to disable automatic reference counting. However, I don't see an option in SwiftPM to put this flag in (aside from
unsafeFlags which defeats the purpose of the library). I have benchmarked it, and this flag improves the performance, so I would really like to continue using it.
On a side note, it seems that not very many of the flags that clang/swiftc has are supported by SwiftPM. This means that many projects will need to make forum posts like this to get them sorted out, which is a cumbersome process for both the project maintainers and the SwiftPM devs. I imagine it hurts adoption, e.g. the Firebase project has the same issue. It seems like SwiftPM should proactively create either a blacklist or a large whitelist of flags, rather than just waiting for devs to create forum threads.