Operations on file names.
Paths which are known to be absolute.
Precondition: The path must be absolute and valid.
Makes the path absolute.
This function may raise an
__IMPOSSIBLE__ error if
canonicalizePath does not return an absolute path.
Tries to establish if the two file paths point to the same file (or directory).
Case-sensitive doesFileExist for Windows. This is case-sensitive only on the file name part, not on the directory part. (Ideally, path components coming from module name components should be checked case-sensitively and the other path components should be checked case insenstively.)