Windows paths attack again. Some paths from the dependency tracker have
mixed folder separators, so comparing textually fail. Additionally some
paths seems to be extended paths (\\?\) which seems not to be liked by
LLVM path utilities.
✔ More informative error messages in case of crashes.
✔ Handling and documenting different cases.
✔ Test cases for different cases.
✔ Make SDKDependencies.swift pass again.