diff --git a/random.nix b/random.nix
index 5429ff0..2150fe2 100644
--- a/random.nix
+++ b/random.nix
@@ -12,7 +12,7 @@ stdenv.mkDerivation rec {
   # OUT shouldn't be needed (and shouldn't have worked), but random
   # developers have forgotten to use PREFIX everywhere,
   makeFlags = ''
-    OUT=$(out)
+    PREFIX=$(out)
   '';
 
   buildInputs = [ gcc ];