diff -r 7a3e67bfa417 -r 16b5df5792a8 mercurial/sslutil.py
--- a/mercurial/sslutil.py	Mon Dec 19 00:28:12 2016 +0530
+++ b/mercurial/sslutil.py	Mon Dec 19 02:15:24 2016 +0530
@@ -668,7 +668,8 @@
       for using system certificate store CAs in addition to the provided
       cacerts file
     """
-    if sys.platform != 'darwin' or util.mainfrozen() or not sys.executable:
+    if (pycompat.sysplatform != 'darwin' or
+                        util.mainfrozen() or not sys.executable):
         return False
     exe = os.path.realpath(sys.executable).lower()
     return (exe.startswith('/usr/bin/python') or
@@ -725,7 +726,7 @@
 
     # The Apple OpenSSL trick isn't available to us. If Python isn't able to
     # load system certs, we're out of luck.
-    if sys.platform == 'darwin':
+    if pycompat.sysplatform == 'darwin':
         # FUTURE Consider looking for Homebrew or MacPorts installed certs
         # files. Also consider exporting the keychain certs to a file during
         # Mercurial install.