Fix ARM build for gcc-4.6

src/arm/stub-cache-arm.cc

 // Copyright 2011 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 1165 matching lines @@
                                         Register scratch1,
                                         Register scratch2,
                                         Register scratch3,
                                         Object* value,
                                         String* name,
                                         Label* miss) {
   // Check that the receiver isn't a smi.
   __ JumpIfSmi(receiver, miss);
 
   // Check that the maps haven't changed.
-  Register reg =
-      CheckPrototypes(object, receiver, holder,
-                      scratch1, scratch2, scratch3, name, miss);
+  CheckPrototypes(object, receiver, holder, scratch1, scratch2, scratch3, name,
+                  miss);
 
   // Return the constant value.
   __ mov(r0, Operand(Handle<Object>(value)));
   __ Ret();
 }
 
 
 MaybeObject* StubCompiler::GenerateLoadCallback(JSObject* object,
                                                 JSObject* holder,
                                                 Register receiver,
@@ skipping 3223 matching lines @@
       masm->isolate()->builtins()->KeyedStoreIC_MissForceGeneric();
   __ Jump(ic, RelocInfo::CODE_TARGET);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM