element-desktop: fix darwin build (#501797)

pkgs/by-name/el/element-desktop/package.nix

@@ -18,6 +18,7 @@
   asar,
   copyDesktopItems,
   darwin,
+  actool,
 }:
 
 let
@@ -58,6 +59,7 @@ stdenv.mkDerivation (
     ]
     ++ lib.optionals stdenv.hostPlatform.isDarwin [
       darwin.autoSignDarwinBinariesHook
+      actool
     ];
 
     inherit seshat;
@@ -163,6 +165,10 @@ stdenv.mkDerivation (
       })
     ];
 
+    stripDebugList = lib.optionals stdenv.hostPlatform.isDarwin [
+      "Applications/Element.app/Contents/MacOS"
+    ];
+
     passthru = {
       # run with: nix-shell ./maintainers/scripts/update.nix --argstr package element-desktop
       updateScript = ./update.sh;