diff -r 238abf65a8ad -r dacfcdd8b94e mercurial/cffi/osutil.py
--- a/mercurial/cffi/osutil.py	Thu Oct 12 09:04:22 2017 -0700
+++ b/mercurial/cffi/osutil.py	Thu Oct 12 23:34:34 2017 -0700
@@ -16,7 +16,7 @@
     pycompat,
 )
 
-if pycompat.sysplatform == 'darwin':
+if pycompat.isdarwin:
     from . import _osutil
 
     ffi = _osutil.ffi