diff --git a/pkgs/development/interpreters/perl/5.20/default.nix b/pkgs/development/interpreters/perl/5.20/default.nix
index 66a9ca597a4..bfd2c26bf70 100644
--- a/pkgs/development/interpreters/perl/5.20/default.nix
+++ b/pkgs/development/interpreters/perl/5.20/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, enableThreading ? true }:
+{ stdenv, fetchurl, enableThreading ? stdenv ? glibc }:
 
 # We can only compile perl with threading on platforms where we have a
 # real glibc in the stdenv.