Issue #767645: Set os.path.supports_unicode_filenames to True in posixpath

Previous commit changed macpath but macpath is not used anymore as os.path
diff --git a/Lib/posixpath.py b/Lib/posixpath.py
index e9f4251..37da71e 100644
--- a/Lib/posixpath.py
+++ b/Lib/posixpath.py
@@ -427,7 +427,7 @@
             path = normpath(resolved)
     return path
 
-supports_unicode_filenames = False
+supports_unicode_filenames = (sys.platform == 'darwin')
 
 def relpath(path, start=None):
     """Return a relative version of a path"""
diff --git a/Misc/NEWS b/Misc/NEWS
index bfa8bac..f4f8da8 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -74,8 +74,7 @@
 
 - logging: Enhanced HTTPHandler with secure and credentials initializers.
 
-- Issue #767645: Set os.path.supports_unicode_filenames to True on Mac OS X
-  (macpath module).
+- Issue #767645: Set os.path.supports_unicode_filenames to True on Mac OS X.
 
 - Issue #9837: The read() method of ZipExtFile objects (as returned by
   ZipFile.open()) could return more bytes than requested.