Improve ctrl-C handling in ninja.py.

tools/ninja.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 import multiprocessing
 import optparse
 import os
 import subprocess
@@ skipping 242 matching lines @@
   if process.returncode != 0:
     NotifyBuildDone(build_config, success=False, start=start_time)
     return 1
   else:
     NotifyBuildDone(build_config, success=True, start=start_time)
 
   return 0
 
 
 def RunOneGomaBuildCommand(args):
-  print ' '.join(args)
-  process = subprocess.Popen(args, stdin=None)
-  process.wait()
-  print (' '.join(args) + " done.")
-  return process.returncode
+  try:
+    print ' '.join(args)
+    process = subprocess.Popen(args, stdin=None)
+    process.wait()
+    print (' '.join(args) + " done.")
+    return process.returncode
+  except KeyboardInterrupt:
+    return 1
 
 
 def Main():
   starttime = time.time()
   # Parse the options.
   parser = BuildOptions()
   (options, args) = parser.parse_args()
   if not ProcessOptions(options, args):
     parser.print_help()
     return 1
@@ skipping 27 matching lines @@
     if r != 0:
       return 1
 
   endtime = time.time()
   print ("The build took %.3f seconds" % (endtime - starttime))
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(Main())