pidgin/pidgin

Don't allow adding a buddy to prpls that don't have an add_buddy callback. Fixes #4061
/*
* Copyright 1986, 1987, 1988 by MIT Information Systems and
* the MIT Student Information Processing Board.
*
* For copyright info, see mit-sipb-copyright.h.
*/
#include <sysdep.h>
extern struct et_list * _et_list;