Issue #5117: Fixed root directory related issue on posixpath.relpath() and
ntpath.relpath().
diff --git a/Lib/ntpath.py b/Lib/ntpath.py
index 11a0a3e..091a242 100644
--- a/Lib/ntpath.py
+++ b/Lib/ntpath.py
@@ -488,8 +488,8 @@
 
     if not path:
         raise ValueError("no path specified")
-    start_list = abspath(start).split(sep)
-    path_list = abspath(path).split(sep)
+    start_list = [x for x in abspath(start).split(sep) if x]
+    path_list = [x for x in abspath(path).split(sep) if x]
     if start_list[0].lower() != path_list[0].lower():
         unc_path, rest = splitunc(path)
         unc_start, rest = splitunc(start)