namedirectory: forward declare dht::crypto::PublicKey

Change-Id: I3fb49911b13cf06e513ff4523a78522a9c2059fc

src/ringdht/namedirectory.cpp

@@ -24,6 +24,7 @@
 #include "fileutils.h"
 #include "base64.h"
 
+#include <opendht/crypto.h>
 #include <msgpack.hpp>
 #include <json/json.h>
 #include <restbed>

src/ringdht/namedirectory.h

@@ -18,12 +18,18 @@
 #pragma once
 
 #include "noncopyable.h"
-#include "opendht/crypto.h"
+
 #include <functional>
 #include <map>
 #include <string>
 #include <mutex>
 
+namespace dht {
+namespace crypto {
+struct PublicKey;
+}
+}
+
 namespace ring {
 
 class NameDirectory