Fix Mac build of r4860...

test/cctest/test-api.cc

 // Copyright 2007-2009 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 9653 matching lines @@
       break;
     case v8::kExternalIntArray:
     case v8::kExternalUnsignedIntArray:
     case v8::kExternalFloatArray:
       return 4;
       break;
     default:
       UNREACHABLE();
       return -1;
   }
+  UNREACHABLE();
+  return -1;
 }
 
 
 template <class ExternalArrayClass, class ElementType>
 static void ExternalArrayTestHelper(v8::ExternalArrayType array_type,
                                     int64_t low,
                                     int64_t high) {
   v8::HandleScope scope;
   LocalContext context;
   const int kElementCount = 40;
@@ skipping 1232 matching lines @@
   const char* code =
       "(function() {"
       "  for (var i = 0; i < 2*16; i++) {"
       "    %_GetFromCache(0, 'a' + i);"
       "  };"
       "  return 'PASSED';"
       "})()";
   v8::internal::Heap::ClearJSFunctionResultCaches();
   ExpectString(code, "PASSED");
 }