diff -r c0a6c19690ff -r 75979c8d4572 mercurial/rcutil.py
--- a/mercurial/rcutil.py	Thu Oct 12 19:20:04 2017 -0700
+++ b/mercurial/rcutil.py	Thu Oct 12 23:30:46 2017 -0700
@@ -15,7 +15,7 @@
     util,
 )
 
-if pycompat.osname == 'nt':
+if pycompat.iswindows:
     from . import scmwindows as scmplatform
 else:
     from . import scmposix as scmplatform