pidgin/pidgin

Don't allow adding a buddy to prpls that don't have an add_buddy callback. Fixes #4061
#include "conversation.h"
PurpleAccount *purple_accounts_find_ext(const char *name, const char *protocol_id,
gboolean (*account_test)(const PurpleAccount *account));
PurpleAccount *purple_accounts_find_any(const char *name, const char *protocol);
PurpleAccount *purple_accounts_find_connected(const char *name, const char *protocol);