Comment 2 for bug 1262380

I'm fairly certain this is a bug in the test itself.

If you take a look at glib2.0/gobject/gmarshal.c g_cclosure_marshal_VOID__PARAM, you see
  typedef void (*GMarshalFunc_VOID__PARAM) (gpointer data1,
                                            gpointer arg_1,
                                            gpointer data2);

That says to me that all of the signal functions in gtk/tests/builder.c should be declared as
signal_normal (GtkWindow *window, GParamSpec *spec)
not
signal_normal (GtkWindow *window, GParamSpec spec)

The "spec" parameter corresponds to "arg_1" in the typedef, which is a pointer.