make compiling a bit cleaner

tdns/Makefile

@@ -1,4 +1,4 @@
-CXXFLAGS:=-std=gnu++14 -Wall -O2 -MMD -MP -ggdb -Iext/simplesocket -Iext/simplesocket/ext/fmt-5.2.1/include -Iext/catch -pthread
+CXXFLAGS:=-std=gnu++14 -Wall -O2 -MMD -MP -ggdb -Iext/simplesocket -Iext/simplesocket/ext/fmt-5.2.1/include -pthread
 CFLAGS:= -Wall -O2 -MMD -MP -ggdb 
 
 PROGRAMS = tdns tdig tres tdns-c-test

tdns/tests.cc

@@ -1,5 +1,5 @@
 #define CATCH_CONFIG_MAIN  // This tells Catch to provide a main() - only do this in one cpp file
-#include "catch.hpp"
+#include "ext/catch/catch.hpp"
 #include "dnsmessages.hh"
 #include "dns-storage.hh"
 

tdns/tres.md

@@ -90,11 +90,9 @@ This requires a recent compiler version that supports C++ 2014. If you
 encounter problems, please let me know (see above for address details).
 
 ```
-$ git clone https://github.com/ahupowerdns/hello-dns.git
+$ git clone --recursive https://github.com/ahupowerdns/hello-dns.git
 $ cd hello-dns/tdns
-$ git submodule init
-$ git submodule update
-$ make
+$ make -j4 tres
 $ ./tres www.powerdns.org A
 ...
 Result or query for www.powerdns.org.|A