--- a/mercurial/pycompat.py	Sat Dec 24 01:16:14 2016 +0530
+++ b/mercurial/pycompat.py	Mon Dec 19 02:35:38 2016 +0530
@@ -45,6 +45,7 @@
     ospathsep = os.pathsep.encode('ascii')
     ossep = os.sep.encode('ascii')
     osaltsep = os.altsep
+    osgetenv = os.getenvb
     if osaltsep:
         osaltsep = osaltsep.encode('ascii')
     # os.getcwd() on Python 3 returns string, but it has os.getcwdb() which
@@ -156,6 +157,7 @@
     sysargv = sys.argv
     sysplatform = sys.platform
     getcwd = os.getcwd
+    osgetenv = os.getenv
 
 stringio = io.StringIO
 empty = _queue.Empty