https://bugs.gentoo.org/932255
--- a/src/filesystem.cpp
+++ b/src/filesystem.cpp
@@ -30,6 +30,7 @@
 #include "serialization/unicode.hpp"
 #include "utils/general.hpp"
 
+#include <boost/filesystem/directory.hpp>
 #include <boost/filesystem/fstream.hpp>
 #include <boost/iostreams/device/file_descriptor.hpp>
 #include <boost/iostreams/stream.hpp>