QUIC: stateless retry. Previously, quic connection object was created when Retry packet was sent. This is neither necessary nor convenient, and contradicts the idea of retry: protecting from bad clients and saving server resources. Now, the connection is not created, token is verified cryptographically instead of holding it in connection.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


cat << END >> $NGX_AUTO_HEADERS_H

#ifndef $have
#define $have  1
#endif

END