Ports of lib9, libbio and libmach to Windows.

R=rsc
https://golang.org/cl/157159
diff --git a/lib/codereview/codereview.py b/lib/codereview/codereview.py
index 0be956b..0d97226 100644
--- a/lib/codereview/codereview.py
+++ b/lib/codereview/codereview.py
@@ -403,7 +403,7 @@
 # Find repository root.  On error, ui.warn and return None
 def RepoDir(ui, repo):
 	url = repo.url();
-	if not url.startswith('file:/'):
+	if not url.startswith('file:'):
 		ui.warn("repository %s is not in local file system\n" % (url,))
 		return None
 	url = url[5:]