mercurial/i18n.py

--- a/mercurial/i18n.py	Thu Oct 12 19:20:04 2017 -0700
+++ b/mercurial/i18n.py	Thu Oct 12 23:30:46 2017 -0700
@@ -29,7 +29,7 @@
     unicode = str
 
 _languages = None
-if (pycompat.osname == 'nt'
+if (pycompat.iswindows
     and 'LANGUAGE' not in encoding.environ
     and 'LC_ALL' not in encoding.environ
     and 'LC_MESSAGES' not in encoding.environ