HTTP/2: invalid connection preface logging (ticket #1981). Previously, invalid connection preface errors were only logged at debug level, providing no visible feedback, in particular, when a plain text HTTP/2 listening socket is erroneously used for HTTP/1.x connections. Now these are explicitly logged at the info level, much like other client-related errors.

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


cat << END >> $NGX_AUTO_CONFIG_H

#ifndef $ngx_param
#define $ngx_param  $ngx_value
#endif

END