I wasted an entire hour today trying to add ghc-prim as a dependency to ghc package but I failed. It's already a dependency transitively (via base), but it was impossible for me to find all the necessary places in our pile of makefiles to update. If anyone knows which files to update I'm happy to do it.
Don't you just add it to Build-Depends in ghc/ghc-bin.cabal.in? (I'm a bit confused because you said the ghc package, did you really mean the ghc-bin package?)
I'd really like to avoid an unnecessary unsafeCoerce here.