code: func (v *Window) SetGravity(gravity gdk.GdkGravity) {
  	C.gtk_window_set_gravity(v.native(), C.GdkGravity(gravity))
  }
docs: // TODO(jrick) GdkGeometry GdkWindowHints.
  /*
  func (v *Window) SetGeometryHints() {
  }
  */
  // SetGravity is a wrapper around gtk_window_set_gravity().