tools: deprecate tlvdump

refs #3196

Change-Id: I7b3925158ec8883d202fcaec497c8c4a3f0cada4
diff --git a/tools/tlvdump.cpp b/tools/tlvdump.cpp
index d45b6f1..ee5088c 100644
--- a/tools/tlvdump.cpp
+++ b/tools/tlvdump.cpp
@@ -171,6 +171,9 @@
 
 int main(int argc, const char *argv[])
 {
+  std::cerr << "tlvdump is deprecated. Use ndn-dissect program from ndn-tools repository.\n"
+               "See `man tlvdump` for details." << std::endl;
+
   if (argc == 1 ||
       (argc == 2 && std::string(argv[1]) == "-"))
     {