diff --git a/src/supertux/game_session.cpp b/src/supertux/game_session.cpp
index 41de52e..a8ebfc9 100644
--- a/src/supertux/game_session.cpp
+++ b/src/supertux/game_session.cpp
@@ -14,6 +14,8 @@
// You should have received a copy of the GNU General Public License
// along with this program. If not, see .
+#include
+
#include "supertux/game_session.hpp"
#include "audio/sound_manager.hpp"