diff --git a/lib/tree.cc b/lib/tree.cc
index 31d3813..f4f360f 100644
--- a/lib/tree.cc
+++ b/lib/tree.cc
@@ -41,6 +41,8 @@
 #include <unistd.h>
 #include <zip.h>
 
+#include <boost/container_hash/hash.hpp>
+
 #include "error.h"
 #include "extra_field.h"
 #include "file_descriptor.h"