diff --git a/src/kits/game/Jamfile b/src/kits/game/Jamfile
index 240a99fabd..cc20c2a569 100644
--- a/src/kits/game/Jamfile
+++ b/src/kits/game/Jamfile
@@ -1,5 +1,7 @@
 SubDir OBOS_TOP src kits game ;
 
+UsePrivateHeaders interface ;
+
 SharedLibrary game :
 	# Public Game Kit
 	DirectWindow.cpp
@@ -17,6 +19,9 @@ SharedLibrary game :
 	GSUtility.cpp
 ;
 
+# Hack to have DirectWindow.cpp include the R5 <Window .h> header.
+PrependObjectHdrs DirectWindow.cpp : /boot/develop/headers/be/interface ;
+
 LinkSharedOSLibs libgame.so :
 	be media
 ;