amber: Fix build (#120126)

Co-authored-by: Sandro <[e-mail]>

pkgs/tools/text/amber/default.nix

···
 { lib, stdenv, fetchFromGitHub, rustPlatform
-, Security
+, libiconv, Security
 }:
 
 rustPlatform.buildRustPackage rec {
···
 
   cargoSha256 = "sha256-opRinhTmhZxpAwHNiVOLXL8boQf09Y1NXrWQ6HWQYQ0=";
 
-  buildInputs = lib.optional stdenv.isDarwin Security;
+  buildInputs = lib.optionals stdenv.isDarwin [ libiconv Security ];
 
   meta = with lib; {
     description = "A code search-and-replace tool";