ion: fix build on darwin

pkgs/shells/ion/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub, rustPlatform }:
+{ stdenv, fetchFromGitHub, rustPlatform, Security }:
 
 rustPlatform.buildRustPackage rec {
   pname = "ion";
@@ -20,6 +20,10 @@ rustPlatform.buildRustPackage rec {
     maintainers = with maintainers; [ dywedir ];
   };
 
+  buildInputs = stdenv.lib.optional stdenv.hostPlatform.isDarwin [
+    Security
+  ];
+
   passthru = {
     shellPath = "/bin/ion";
   };