diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 24c28c46f35..df9de2bc0ee 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -6699,7 +6699,11 @@ let
   libmsgpack = callPackage ../development/libraries/libmsgpack { };
   libmsgpack_0_5 = callPackage ../development/libraries/libmsgpack/0.5.nix { };
 
-  libnatspec = callPackage ../development/libraries/libnatspec { };
+  libnatspec = callPackage ../development/libraries/libnatspec (
+    stdenv.lib.optionalAttrs stdenv.isDarwin {
+      inherit (darwin) libiconv;
+    }
+  );
 
   libndp = callPackage ../development/libraries/libndp { };