Introduce intrinsic to expose debug state to generated code.

src/macros.py

 # Copyright 2006-2009 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 267 matching lines @@
 # Matches PropertyAttributes from property-details.h
 const PROPERTY_ATTRIBUTES_NONE = 0;
 const PROPERTY_ATTRIBUTES_STRING = 8;
 const PROPERTY_ATTRIBUTES_SYMBOLIC = 16;
 const PROPERTY_ATTRIBUTES_PRIVATE_SYMBOL = 32;
 
 # Use for keys, values and entries iterators.
 const ITERATOR_KIND_KEYS = 1;
 const ITERATOR_KIND_VALUES = 2;
 const ITERATOR_KIND_ENTRIES = 3;
+
+# Check whether debug is active.
+const DEBUG_IS_ACTIVE = (%_DebugIsActive() != 0);