Make git-cl and update_depot_tools msys-compatible.

git-cl

Index: git-cl
===================================================================
--- git-cl	(revision 87505)
+++ git-cl	(working copy)
@@ -1,5 +1,5 @@
 #!/bin/sh
-# Copyright (c) 2010 The Chromium Authors. All rights reserved.
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
@@ -9,4 +9,14 @@
 base_dir=$(dirname "$0")
 
 "$base_dir"/update_depot_tools
-"$base_dir"/git_cl.py "$@"
+
+# Test if this script is running under a MSys install.  If it is, we will
+# hardcode the path to Python where possible.
+OUTPUT="$(uname | grep 'MINGW')"
+MINGW=$?
+
+if [ -d "$base_dir/python_bin" -a $MINGW = 0 ]; then
+  exec "$base_dir/python_bin/python.exe" "$base_dir"/git_cl.py "$@"
+else
+  exec "$base_dir/git_cl.py" "$@"
+fi