sheets_dialog.c:254:24: warning: incompatible pointer types passing 'GObject *' (aka 'struct _GObject *') to parameter of type 'GtkObject *' (aka 'struct _GtkObject *') [-Wincompatible-pointer-types]
  gtk_object_set_data (G_OBJECT (sheets_shapeselection_dialog), "sheets_shapeselection_dialog", sheets_shapeselection_dialog);
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/glib-2.0/gobject/gobject.h:51:37: note: expanded from macro 'G_OBJECT'
                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/gtk-2.0/gtk/gtkobject.h:181:49: note: passing argument to parameter 'object' here
void     gtk_object_set_data         (GtkObject      *object,
                                                      ^
sheets_dialog.c:258:24: warning: incompatible pointer types passing 'GObject *' (aka 'struct _GObject *') to parameter of type 'GtkObject *' (aka 'struct _GtkObject *') [-Wincompatible-pointer-types]
  gtk_object_set_data (G_OBJECT (sheets_shapeselection_dialog), "ok_button", ok_button);
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/glib-2.0/gobject/gobject.h:51:37: note: expanded from macro 'G_OBJECT'
                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/gtk-2.0/gtk/gtkobject.h:181:49: note: passing argument to parameter 'object' here
void     gtk_object_set_data         (GtkObject      *object,
                                                      ^
sheets_dialog.c:267:24: warning: incompatible pointer types passing 'GObject *' (aka 'struct _GObject *') to parameter of type 'GtkObject *' (aka 'struct _GtkObject *') [-Wincompatible-pointer-types]
  gtk_object_set_data (G_OBJECT (sheets_shapeselection_dialog), "cancel_button1", cancel_button1);
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/glib-2.0/gobject/gobject.h:51:37: note: expanded from macro 'G_OBJECT'
                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/gtk-2.0/gtk/gtkobject.h:181:49: note: passing argument to parameter 'object' here
void     gtk_object_set_data         (GtkObject      *object,
                                                      ^