diff --git a/real/ben-raytrace/Makefile b/real/ben-raytrace/Makefile
index 55762b52629eac44eb57815f2b73f00d9d08adec..e1443f8e57489d27bc6b87011bbe7cfc0fad1282 100644
--- a/real/ben-raytrace/Makefile
+++ b/real/ben-raytrace/Makefile
@@ -3,5 +3,7 @@ include $(TOP)/mk/boilerplate.mk
 
 SRC_DEPS = binary bytestring array parallel primitive transformers mtl ghc-prim random
 
+ALL_DIRS += Random SamplerMonad Scene
+
 include $(TOP)/mk/target.mk