在vala中哪里可以找到Glib对象？

class Demo.Hello : Glib.Object
{
  public static int main( string[] args )
  {
    stdout.printf(\"Hello, Vala!\\n\");
    return 0;
  }
}

$ valac hello.vala 
hello.vala:1.20-1.23: error: The symbol `Glib\' could not be found
class Demo.Hello : Glib.Object
                   ^^^^
Compilation failed: 1 error(s), 0 warning(s)
[1]+  Done                    gvim hello.vala

Glib.Object

Glib.

class Demo.Hello : Object

$ valac --version
Vala 0.5.2