diff -r 570ea0259b0a -r 5b39503157fd mercurial/posix.py
--- a/mercurial/posix.py	Fri Jul 22 10:31:56 2011 +0200
+++ b/mercurial/posix.py	Fri Jul 22 10:35:05 2011 +0200
@@ -340,3 +340,11 @@
 
 def lookupreg(key, name=None, scope=None):
     return None
+
+def hidewindow():
+    """Hide current shell window.
+
+    Used to hide the window opened when starting asynchronous
+    child process under Windows, unneeded on other systems.
+    """
+    pass