ninja windows: make sure that .s files aren't passed to compiler

test/win/gyptest-asm-files.py

+#!/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 .s files aren't passed to cl.
+"""
+
+import TestGyp
+
+import sys
+
+if sys.platform == 'win32':
+  test = TestGyp.TestGyp(formats=['msvs', 'ninja'])
+
+  CHDIR = 'asm-files'
+  test.run_gyp('asm-files.gyp', chdir=CHDIR)
+  # The compiler will error out if it's passed the .s files, so just make sure
+  # the build succeeds. The compiler doesn't directly support building
+  # assembler files on Windows, they have to be built explicitly with a
+  # third-party tool.
+  test.build('asm-files.gyp', test.ALL, chdir=CHDIR)
+
+  test.pass_test()