so on null event handler

[liquidatom]

i'm trying to handler http request on single endpoint, so i specified handler like this:
mg_bind(m_mgr, port, nullptr); // i don't need handle other requests
mg_register_http_endpoint(m_conn, "/path", pathHandler);

---

mongoose fail with stack overflow when mg_call try to call default handler for HTTP mg_http_handler and so on
mg_call:
if (ev_handler == NULL) {
/*
* If protocol handler is specified, call it. Otherwise, call user-specified
* event handler.
*/
ev_handler = nc->proto_handler ? nc->proto_handler : nc->handler;
}

---

ev_handler(nc, ev, ev_data MG_UD_ARG(user_data)); // calling mg_http_handler

and in mg_http_handler we have:
mg_call(nc, nc->handler, nc->user_data, ev, ev_data);

---

not sure how it can be correctly resolved, but it seems strange that mg_http_handler can call parent function(mg_call)

[dimonomid]

The handler for mg_bind is required, don't pass NULL there. Provide an empty implementation of the handler at least.

We should fix mg_bind to return NULL if passed a NULL handler though.