claws-mail maildir++ plugin compiler warnings

maildir_gtk.c: In function ‘remove_mailbox_cb’:
maildir_gtk.c:289:6: warning: passing argument 7 of ‘alertpanel_full’ makes integer from pointer without a cast [-Wint-conversion]
      NULL, ALERT_WARNING, G_ALERTDEFAULT);
      ^~~~
In file included from maildir_gtk.c:36:
/usr/include/claws-mail/alertpanel.h:59:20: note: expected ‘gboolean’ {aka ‘int’} but argument is of type ‘void *’
       gboolean     can_disable,
       ~~~~~~~~~~~~~^~~~~~~~~~~
maildir_gtk.c:289:12: warning: passing argument 8 of ‘alertpanel_full’ makes pointer from integer without a cast [-Wint-conversion]
      NULL, ALERT_WARNING, G_ALERTDEFAULT);
            ^~~~~~~~~~~~~
In file included from maildir_gtk.c:36:
/usr/include/claws-mail/alertpanel.h:60:20: note: expected ‘GtkWidget *’ {aka ‘struct _GtkWidget *’} but argument is of type ‘int’
       GtkWidget   *widget,
       ~~~~~~~~~~~~~^~~~~~
maildir_gtk.c: In function ‘delete_folder_cb’:
maildir_gtk.c:321:6: warning: passing argument 7 of ‘alertpanel_full’ makes integer from pointer without a cast [-Wint-conversion]
      NULL, ALERT_NOTICE, G_ALERTDEFAULT);
      ^~~~
In file included from maildir_gtk.c:36:
/usr/include/claws-mail/alertpanel.h:59:20: note: expected ‘gboolean’ {aka ‘int’} but argument is of type ‘void *’
       gboolean     can_disable,
       ~~~~~~~~~~~~~^~~~~~~~~~~