More changes to use #ifndef PRODUCT ... #endif explicitly instead of relying on compiler magic.

runtime/vm/flags.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/flags.h"
 
 #include "platform/assert.h"
 #include "vm/json_stream.h"
 #include "vm/os.h"
 
@@ skipping 469 matching lines @@
 
 
 void Flags::PrintFlags() {
   OS::Print("Flag settings:\n");
   for (intptr_t i = 0; i < num_flags_; ++i) {
     flags_[i]->Print();
   }
 }
 
 
+#ifndef PRODUCT
 void Flags::PrintFlagToJSONArray(JSONArray* jsarr, const Flag* flag) {
   if (!FLAG_support_service) {
     return;
   }
   if (flag->IsUnrecognized() || flag->type_ == Flag::kFunc) {
     return;
   }
   JSONObject jsflag(jsarr);
   jsflag.AddProperty("name", flag->name_);
   jsflag.AddProperty("comment", flag->comment_);
@@ skipping 35 matching lines @@
   if (!FLAG_support_service) {
     return;
   }
   JSONObject jsobj(js);
   jsobj.AddProperty("type", "FlagList");
   JSONArray jsarr(&jsobj, "flags");
   for (intptr_t i = 0; i < num_flags_; ++i) {
     PrintFlagToJSONArray(&jsarr, flags_[i]);
   }
 }
+#endif  // !PRODUCT
 
 }  // namespace dart