made it work properly when building with stats logging

src/session_impl.cpp

@@ -625,6 +625,7 @@ namespace detail
 			"\n";
 		m_buffer_usage_logger.open("buffer_stats.log", std::ios::trunc);
 		m_second_counter = 0;
+		m_buffer_allocations = 0;
 #endif
 
 		// ---- generate a peer id ----

src/ut_metadata.cpp

@@ -56,6 +56,9 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/extensions.hpp"
 #include "libtorrent/extensions/metadata_transfer.hpp"
 #include "libtorrent/alert_types.hpp"
+#ifdef TORRENT_STATS
+#include "libtorrent/aux_/session_impl.hpp"
+#endif
 
 namespace libtorrent { namespace
 {