xss-locker: improve options passing

- allow locker options without hacks
- add extraOptions

nixos/modules/programs/xss-lock.nix

@@ -8,12 +8,23 @@ in
 {
   options.programs.xss-lock = {
     enable = mkEnableOption "xss-lock";
+
     lockerCommand = mkOption {
       default = "${pkgs.i3lock}/bin/i3lock";
       example = literalExample ''''${pkgs.i3lock-fancy}/bin/i3lock-fancy'';
       type = types.string;
       description = "Locker to be used with xsslock";
     };
+
+    extraOptions = mkOption {
+      default = [ ];
+      example = literalExample [ "--ignore-sleep" ];
+      type = types.listOf types.str;
+      description = ''
+        Additional command-line arguments to pass to
+        <command>xss-lock</command>.
+      '';
+    };
   };
 
   config = mkIf cfg.enable {
@@ -21,7 +32,13 @@ in
       description = "XSS Lock Daemon";
       wantedBy = [ "graphical-session.target" ];
       partOf = [ "graphical-session.target" ];
-      serviceConfig.ExecStart = "${pkgs.xss-lock}/bin/xss-lock ${cfg.lockerCommand}";
+      serviceConfig.ExecStart = with lib;
+        strings.concatStringsSep " " ([
+            "${pkgs.xss-lock}/bin/xss-lock"
+          ] ++ cfg.extraOptions ++ [
+            "--"
+            cfg.lockerCommand
+        ]);
     };
   };
 }