diff -r 238abf65a8ad -r dacfcdd8b94e mercurial/posix.py
--- a/mercurial/posix.py	Thu Oct 12 09:04:22 2017 -0700
+++ b/mercurial/posix.py	Thu Oct 12 23:34:34 2017 -0700
@@ -332,7 +332,7 @@
 # fallback normcase function for non-ASCII strings
 normcasefallback = normcase
 
-if pycompat.sysplatform == 'darwin':
+if pycompat.isdarwin:
 
     def normcase(path):
         '''