Kill off the SCons based build.

SConstruct

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 1139 matching lines @@
   'vfp3': {
     'values': ['on', 'off'],
     'default': 'on',
     'help': 'use vfp3 instructions when building the snapshot [Arm only]'
   },
   'fpu': {
     'values': ['on', 'off'],
     'default': 'on',
     'help': 'use fpu instructions when building the snapshot [MIPS only]'
   },
+  'I_know_I_should_build_with_GYP': {
+    'values': ['yes', 'no'],
+    'default': 'no',
+    'help': 'grace period: temporarily override SCons deprecation'
+  }
 
 }
 
 ALL_OPTIONS = dict(PLATFORM_OPTIONS, **SIMPLE_OPTIONS)
 
 
 def AddOptions(options, result):
   guess_env = Environment(options=result)
   for (name, option) in options.iteritems():
     if 'guess' in option:
@@ skipping 80 matching lines @@
 
 def IsLegal(env, option, values):
   str = env[option]
   for s in SplitList(str):
     if not s in values:
       Abort("Illegal value for option %s '%s'." % (option, s))
       return False
   return True
 
 
+def WarnAboutDeprecation():
+  print """
+    #####################################################################
+    #                                                                   #
+    #  LAST WARNING: Building V8 with SCons is deprecated.              #
+    #                                                                   #
+    #  This only works because you have overridden the kill switch.     #
+    #                                                                   #
+    #              MIGRATE TO THE GYP-BASED BUILD NOW!                  #
+    #                                                                   #
+    #  Instructions: http://code.google.com/p/v8/wiki/BuildingWithGYP.  #
+    #                                                                   #
+    #####################################################################
+  """
+
+
 def VerifyOptions(env):
+  if env['I_know_I_should_build_with_GYP'] != 'yes':
+    Abort("Building V8 with SCons is no longer supported. Please use GYP "
+          "instead; you can find instructions are at "
+          "http://code.google.com/p/v8/wiki/BuildingWithGYP.\n\n"
+          "Quitting.\n\n"
+          "For a limited grace period, you can specify "
+          "\"I_know_I_should_build_with_GYP=yes\" to override.")
+  else:
+    WarnAboutDeprecation()
+    import atexit
+    atexit.register(WarnAboutDeprecation)
+
   if not IsLegal(env, 'mode', ['debug', 'release']):
     return False
   if not IsLegal(env, 'sample', ["shell", "process", "lineprocessor"]):
     return False
   if not IsLegal(env, 'regexp', ["native", "interpreted"]):
     return False
   if env['os'] == 'win32' and env['library'] == 'shared' and env['prof'] == 'on':
     Abort("Profiling on windows only supported for static library.")
   if env['gdbjit'] == 'on' and ((env['os'] != 'linux' and env['os'] != 'macos') or (env['arch'] != 'ia32' and env['arch'] != 'x64' and env['arch'] != 'arm')):
     Abort("GDBJIT interface is supported only for Intel-compatible (ia32 or x64) Linux/OSX target.")
@@ skipping 322 matching lines @@
 # We disable deprecation warnings because we need to be able to use
 # env.Copy without getting warnings for compatibility with older
 # version of scons.  Also, there's a bug in some revisions that
 # doesn't allow this flag to be set, so we swallow any exceptions.
 # Lovely.
 try:
   SetOption('warn', 'no-deprecated')
 except:
   pass
 
-
-def WarnAboutDeprecation():
-  print """
-#######################################################
-#  WARNING: Building V8 with SCons is deprecated and  #
-#  will not work much longer. Please switch to using  #
-#  the GYP-based build now. Instructions are at       #
-#  http://code.google.com/p/v8/wiki/BuildingWithGYP.  #
-#######################################################
-  """
-
-WarnAboutDeprecation()
-import atexit
-atexit.register(WarnAboutDeprecation)
 Build()