--- a/mercurial/mail.py	Mon Mar 13 08:53:31 2017 -0700
+++ b/mercurial/mail.py	Mon Mar 13 09:11:08 2017 -0700
@@ -353,4 +353,4 @@
         except UnicodeDecodeError:
             pass
         uparts.append(part.decode('ISO-8859-1'))
-    return encoding.tolocal(u' '.join(uparts).encode('UTF-8'))
+    return encoding.unitolocal(u' '.join(uparts))