The need for GHC.SystemTools.Archive

Building -staticlib required the presence of libtool, and was a such restricted to mach-o only. As libtool on macOS and gnu libtool are very different, there was no simple portable way to support this.

libtool for static archives does essentially: concatinate the input archives, add the input objects, and create a symbol index. Using ar for this task fails as even ar (bsd and gnu, llvm, ...) do not provide the same features across platforms (e.g. index prefixed retrieval of objects with the same name.)

As Archives are rather simple structurally, we can just build the archives with Haskell directly and use ranlib on the final result to get the symbol index. This should allow us to work around with the differences/abailability of libtool across differet platforms.

NB: Supplants Ar.