Lua : add extern for jit utilities

std/lua/jit/Jit.hx

@@ -0,0 +1,21 @@
+package lua.jit;
+
+import haxe.Constraints.Function;
+
+#if lua_jit
+@:native("_G.jit")
+extern class Jit {
+	public static function on(?f:Function, ?recursive:Bool) : Void;
+	public static function off(?f:Function, ?recursive:Bool) : Void;
+	public static function flush(?f:Function, ?recursive:Bool) : Void;
+	public static function status() : Bool;
+	public static var version : String;
+	public static var version_num : Int;
+	public static var os : String;
+	public static var arch : String;
+	public static var opt : { start : Function };
+	public static var util : Dynamic;
+}
+#end
+
+