[NaCl SDK] Convert python scripts from optparse to argparse.

native_client_sdk/src/build_tools/generate_notice.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Build the NOTICE file distributed with the NaCl SDK from a set of given
 license files."""
 
-import optparse
+import argparse
 import os
 import sys
 
 
 def Trace(msg):
   if Trace.verbose:
     print msg
 
 Trace.verbose = False
 
@@ skipping 41 matching lines @@
   license_dict = CreateLicenseDict(found_files)
   with open(output_filename, 'w') as output_file:
     for i, license_filenames in enumerate(sorted(license_dict.iterkeys())):
       license_text = license_dict[license_filenames]
       if i:
         output_file.write('\n\n\n')
       WriteLicense(output_file, root, license_text, license_filenames)
 
 
 def main(args):
-  parser = optparse.OptionParser()
-  parser.add_option('-v', '--verbose', help='Verbose output.',
+  parser = argparse.ArgumentParser(description=__doc__)
+  parser.add_argument('-v', '--verbose', help='Verbose output.',
       action='store_true')
-  parser.add_option('-o', '--output', help='Output file')
-  parser.add_option('--root', help='Root for all paths')
+  parser.add_argument('-o', '--output', help='Output file')
+  parser.add_argument('--root', help='Root for all paths')
+  parser.add_argument('files', nargs='*')
 
-  options, args = parser.parse_args(args)
+  options = parser.parse_args(args)
   Trace.verbose = options.verbose
 
   if not options.output:
     parser.error('No output file given. See -o.')
   if not options.root:
     parser.error('No root directory given. See --root.')
 
-  Generate(options.output, options.root, args)
+  Generate(options.output, options.root, options.files)
   Trace('Done.')
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))