Enable conditional directives by default.

runtime/vm/parser.cc

 // Copyright (c) 2012, 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.
 
 #include "vm/parser.h"
 #include "vm/flags.h"
 
 #ifndef DART_PRECOMPILED_RUNTIME
 
 #include "lib/invocation_mirror.h"
@@ skipping 26 matching lines @@
 #include "vm/tags.h"
 #include "vm/timeline.h"
 #include "vm/timer.h"
 #include "vm/zone.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, enable_debug_break, false, "Allow use of break \"message\".");
 DEFINE_FLAG(bool, trace_parser, false, "Trace parser operations.");
 DEFINE_FLAG(bool, warn_mixin_typedef, true, "Warning on legacy mixin typedef.");
-DEFINE_FLAG(bool, conditional_directives, false,
+// TODO(floitsch): remove the conditional-directive flag, once we publicly
+// committed to the current version.
+DEFINE_FLAG(bool, conditional_directives, true,
     "Enable conditional directives");
 DEFINE_FLAG(bool, warn_super, false,
     "Warning if super initializer not last in initializer list.");
 DEFINE_FLAG(bool, await_is_keyword, false,
     "await and yield are treated as proper keywords in synchronous code.");
 
 DECLARE_FLAG(bool, profile_vm);
 DECLARE_FLAG(bool, trace_service);
 
 // Quick access to the current thread, isolate and zone.
@@ skipping 14421 matching lines @@
     const ArgumentListNode& function_args,
     const LocalVariable* temp_for_last_arg,
     bool is_super_invocation) {
   UNREACHABLE();
   return NULL;
 }
 
 }  // namespace dart
 
 #endif  // DART_PRECOMPILED_RUNTIME