Fix compilation with Boost 1.65.0

Change-Id: Ib88b7e13bddb1728dd882c086e97edffdd696f0d
Refs: #4258
diff --git a/tools/ndn-autoconfig/ndn-fch-discovery.cpp b/tools/ndn-autoconfig/ndn-fch-discovery.cpp
index 01c169e..395d9f9 100644
--- a/tools/ndn-autoconfig/ndn-fch-discovery.cpp
+++ b/tools/ndn-autoconfig/ndn-fch-discovery.cpp
@@ -24,8 +24,11 @@
  */
 
 #include "ndn-fch-discovery.hpp"
-#include <boost/regex.hpp>
+
 #include <boost/algorithm/string.hpp>
+#include <boost/regex.hpp>
+
+#include <sstream>
 
 namespace ndn {
 namespace tools {