--- a/mercurial/dispatch.py	Mon Oct 02 06:52:10 2017 +0100
+++ b/mercurial/dispatch.py	Mon Oct 02 07:18:24 2017 +0100
@@ -75,6 +75,7 @@
 
 def run():
     "run the command in sys.argv"
+    _initstdio()
     req = request(pycompat.sysargv[1:])
     err = None
     try:
@@ -95,6 +96,10 @@
         req.ui.ferr.flush()
     sys.exit(status & 255)
 
+def _initstdio():
+    for fp in (sys.stdin, sys.stdout, sys.stderr):
+        util.setbinary(fp)
+
 def _getsimilar(symbols, value):
     sim = lambda x: difflib.SequenceMatcher(None, value, x).ratio()
     # The cutoff for similarity here is pretty arbitrary. It should