diff --git a/pkgs/development/libraries/flint/default.nix b/pkgs/development/libraries/flint/default.nix
index 20a80119b13..462d186c72d 100644
--- a/pkgs/development/libraries/flint/default.nix
+++ b/pkgs/development/libraries/flint/default.nix
@@ -39,7 +39,7 @@ stdenv.mkDerivation rec {
   ];
 
   # issues with ntl -- https://github.com/wbhart/flint2/issues/487
-  NIX_CXXSTDLIB_COMPILE = [ "-std=c++11" ];
+  NIX_CXXSTDLIB_COMPILE = "-std=c++11";
 
   patches = [
     (fetchpatch {