diff --git a/pkgs/development/interpreters/pyrex/0.9.6.nix b/pkgs/development/interpreters/pyrex/0.9.6.nix
index c2ccae71eff..d79cd58c159 100644
--- a/pkgs/development/interpreters/pyrex/0.9.6.nix
+++ b/pkgs/development/interpreters/pyrex/0.9.6.nix
@@ -1,4 +1,4 @@
-{ fetchurl, python2Packages }:
+{ stdenv, fetchurl, python2Packages }:
 
 let version = "0.9.6.4"; in