Issue #21840: Fixed expanding unicode variables of form $var in
posixpath.expandvars().  Fixed all os.path implementations on
unicode-disabled builds.
diff --git a/Lib/macpath.py b/Lib/macpath.py
index c31bdaa..9ebd83c 100644
--- a/Lib/macpath.py
+++ b/Lib/macpath.py
@@ -5,6 +5,7 @@
 from stat import *
 import genericpath
 from genericpath import *
+from genericpath import _unicode
 
 __all__ = ["normcase","isabs","join","splitdrive","split","splitext",
            "basename","dirname","commonprefix","getsize","getmtime",
@@ -186,7 +187,7 @@
 def abspath(path):
     """Return an absolute path."""
     if not isabs(path):
-        if isinstance(path, unicode):
+        if isinstance(path, _unicode):
             cwd = os.getcwdu()
         else:
             cwd = os.getcwd()