diff --git a/pkgs/games/the-butterfly-effect/default.nix b/pkgs/games/the-butterfly-effect/default.nix
index bd1885f9bd9..caea5b4bb4f 100644
--- a/pkgs/games/the-butterfly-effect/default.nix
+++ b/pkgs/games/the-butterfly-effect/default.nix
@@ -1,5 +1,5 @@
 x@{builderDefsPackage
-  , qt4, box2d
+  , qt4, box2d, which
   ,fetchsvn
   , ...}:
 builderDefsPackage