Add "standalone_static_library" flag

test/configurations/invalid/standalone_static_library.gyp

Index: test/configurations/invalid/standalone_static_library.gyp
===================================================================
--- test/configurations/invalid/standalone_static_library.gyp	(revision 0)
+++ test/configurations/invalid/standalone_static_library.gyp	(revision 0)
@@ -0,0 +1,17 @@
+# 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.
+
+{
+  'targets': [
+    {
+      'target_name': 'configurations',
+      'type': 'none',
+      'configurations': {
+        'Debug': {
+          'standalone_static_library': 1,
+        },
+      }
+    },
+  ],
+}