msvs: fix regression in r1378, environment not set up properly for multiple actions on one input

test/many-actions/gyptest-many-actions-unsorted.py

Index: test/many-actions/gyptest-many-actions-unsorted.py
diff --git a/test/many-actions/gyptest-many-actions-unsorted.py b/test/many-actions/gyptest-many-actions-unsorted.py
new file mode 100644
index 0000000000000000000000000000000000000000..c2d13a98b0139b451aa470bad8f07cd9b73eec60
--- /dev/null
+++ b/test/many-actions/gyptest-many-actions-unsorted.py
@@ -0,0 +1,20 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Make sure lots of actions in the same target don't cause exceeding command
+line length.
+"""
+
+import TestGyp
+
+test = TestGyp.TestGyp()
+
+test.run_gyp('many-actions-unsorted.gyp')
+test.build('many-actions-unsorted.gyp', test.ALL)
+for i in range(15):
+  test.built_file_must_exist('generated_%d.h' % i)
+test.pass_test()