Fix build

runtime/vm/flow_graph_compiler_x64.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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 891 matching lines @@
 }
 
 
 // TODO(srdjan): Investigate where to put the argument type checks for
 // checked mode.
 void FlowGraphCompiler::CompileGraph() {
   // Specialized version of entry code from CodeGenerator::GenerateEntryCode.
   const Function& function = parsed_function_.function();
 
   const int parameter_count = function.num_fixed_parameters();
-  const int num_opt_params = function.num_optional_parameters();
   const int num_copied_params = parsed_function_.copied_parameter_count();
   const int local_count = parsed_function_.stack_local_count();
   __ EnterFrame(StackSize() * kWordSize);
 
   // We check the number of passed arguments when we have to copy them due to
   // the presence of optional named parameters.
   // No such checking code is generated if only fixed parameters are declared,
   // unless we are debug mode or unless we are compiling a closure.
   if (num_copied_params == 0) {
 #ifdef DEBUG
@@ skipping 113 matching lines @@
 void FlowGraphCompiler::FinalizeExceptionHandlers(const Code& code) {
   // We don't compile exception handlers yet.
   code.set_exception_handlers(
       ExceptionHandlers::Handle(ExceptionHandlers::New(0)));
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64