diff --git a/random.nix b/random.nix
index 42ad351..5bf0f44 100644
--- a/random.nix
+++ b/random.nix
@@ -9,9 +9,15 @@ stdenv.mkDerivation rec {
     sha256 = "1izkzy952rjzlk3d9ndp3bklxc45gkwvpw0376x39flq1km0kyak";
   };
 
+  # OUT shouldn't be needed (and shouldn't have worked), but random
+  # developers have forgotten to use PREFIX everywhere,
+  makeFlags = ''
+    OUT=$(out)
+  '';
+
   buildInputs = [ gcc ];
   buildPhase = "make build";
-  installPhase = "make install OUT=\$out";
+  installPhase = "make install";
 
   meta = with stdenv.lib; {
     description = "Program thas exit with 0 or 1 randomly";