--- tcptrack-1.3.0.old/src/util.cc
+++ tcptrack-1.3.0/src/util.cc
@@ -21,6 +21,8 @@
  */
 #include "util.h"
 #include <stdio.h>
+#include <string.h>
+
 #include "headers.h"
 #ifdef HAVE_HASH_MAP
 # include <hash_map>