change order of gpointer data; field in struct _GNode to be partly binary

change order of gpointer data; field in struct _GNode to be partly binary

Mon Aug  3 16:02:26 1998  Tim Janik  <timj@gtk.org>

        * glib.h:
        * gnode.c: change order of gpointer data; field in struct _GNode to
        be partly binary compatible with GList and GSList.