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

native_client_sdk/src/tools/ncval.py

Index: native_client_sdk/src/tools/ncval.py
diff --git a/native_client_sdk/src/tools/ncval.py b/native_client_sdk/src/tools/ncval.py
index aebfe34afaafcdcaeef68d0b10aa429bf5e700f3..84903991c2d5e8ec5628c34666fb61c222f20198 100755
--- a/native_client_sdk/src/tools/ncval.py
+++ b/native_client_sdk/src/tools/ncval.py
@@ -3,10 +3,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-"""Wrapper script for running ncval.
+"""Wrapper script for running the Native Client validator (ncval).
 """
 
-import optparse
+import argparse
 import os
 import subprocess
 import sys
@@ -28,12 +28,11 @@ def Log(msg):
     sys.stderr.write(str(msg) + '\n')
 Log.verbose = False
 
-def main(argv):
-  usage = 'Usage: %prog [options] <.nexe | .so>'
-  epilog = 'Example: ncval.py my_nexe.nexe'
-  parser = optparse.OptionParser(usage, description=__doc__, epilog=epilog)
-  parser.add_option('-v', '--verbose', action='store_true',
-                    help='Verbose output')
+def main(args):
+  parser = argparse.ArgumentParser(description=__doc__)
+  parser.add_argument('-v', '--verbose', action='store_true',
+                      help='Verbose output')
+  parser.add_argument('nexe', metavar="EXE", help='Executable to validate')
 
   # To enable bash completion for this command first install optcomplete
   # and then add this line to your .bashrc:
@@ -44,11 +43,9 @@ def main(argv):
   except ImportError:
     pass
 
-  options, args = parser.parse_args(argv)
-  if not args:
-    parser.error('No executable file specified')
+  options = parser.parse_args(args)
+  nexe = options.nexe
 
-  nexe = args[0]
   if options.verbose:
     Log.verbose = True