Try to fix non-existent builds

Somehow I'm ending up with no file. Try to diagnose why, but also try to
fix it at the same problem without being 100% sure of the root cause

flake.nix

@@ -83,11 +83,18 @@
                     }
                   );
                 in
-                pkgs.writeShellScriptBin "package-sword" ''
-                  out=$(pwd)
-                  pushd ${svnSword}
-                  ${pkgs.gnutar}/bin/tar cvhaf $out/sword.tar.xz * --transform "s+^+sword/+"
-                '';
+                pkgs.writeShellApplication {
+                  name = "package-sword";
+                  runtimeInputs = with pkgs; [
+                    gnutar
+                    xz
+                  ];
+                  text = ''
+                    out=$(pwd)
+                    pushd ${svnSword}
+                    tar cvhaf "$out/sword.tar.xz" ./* --transform "s+^\\./+sword/+"
+                  '';
+                };
             in
             with pkgs.pkgsCross;
             {