[NaCl SDK] nacl_io: Fix real_node when dealing with a windows terminal

native_client_sdk/src/libraries/nacl_io/dir_node.cc

Index: native_client_sdk/src/libraries/nacl_io/dir_node.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/dir_node.cc b/native_client_sdk/src/libraries/nacl_io/dir_node.cc
index 6cf0656d04365c5107f75711dc3c7970c5f2d323..f8b23e12b9d575cc8ba5641758640fe813b59a5b 100644
--- a/native_client_sdk/src/libraries/nacl_io/dir_node.cc
+++ b/native_client_sdk/src/libraries/nacl_io/dir_node.cc
@@ -92,7 +92,7 @@ Error DirNode::AddChild(const std::string& name, const ScopedNode& node) {
 
   NodeMap_t::iterator it = map_.find(name);
   if (it != map_.end()) {
-    LOG_TRACE("Can't add child \"%s\", it already exists.", name);
+    LOG_TRACE("Can't add child \"%s\", it already exists.", name.c_str());
     return EEXIST;
   }