swift-package-manager

[Xcodeproj] Switch back to lib<name> based product names.

 - This is another thing we need for SwiftPM itself (so the LLVM JIT can locate
   the `PackageDescription` library as part of our `Package.swift` loading
   process). In this case, it is the right convention for DSOs,
   regardless. However, we will probably need to find another solution for this
   if we want to move to building frameworks for library targets.