diff --git a/pkgs/development/libraries/gmp/default.nix b/pkgs/development/libraries/gmp/default.nix
index 459a57ab5ca..0b472928d0e 100644
--- a/pkgs/development/libraries/gmp/default.nix
+++ b/pkgs/development/libraries/gmp/default.nix
@@ -1,4 +1,4 @@
-{stdenv, fetchurl, m4, cxx ? true }:
+{stdenv, fetchurl, m4, cxx ? true}:
 
 stdenv.mkDerivation {
   name = "gmp-4.2.4";