ninja windows: don't print blank lines in RC wrapper

pylib/gyp/win_tool.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.
 
 """Utility functions for Windows builds.
 
 These functions are executed via gyp-win-tool when using the ninja generator.
 """
@@ skipping 80 matching lines @@
     return popen.returncode
 
   def ExecRcWrapper(self, *args):
     """Filter logo banner from invocations of rc.exe. Older versions of RC
     don't support the /nologo flag."""
     popen = subprocess.Popen(
         args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
     out, _ = popen.communicate()
     for line in out.splitlines():
       if (not line.startswith('Microsoft (R) Windows (R) Resource Compiler') and
-          not line.startswith('Copyright (C) Microsoft Corporation')):
+          not line.startswith('Copyright (C) Microsoft Corporation') and
+          line):
         print line
     return popen.returncode
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))