HTTP/2: fixed null pointer dereference with server push. r->headers_in.host can be NULL in ngx_http_v2_push_resource(). This happens when a request is terminated with 400 before the :authority or Host header is parsed, and either pushing is enabled on the server{} level or error_page 400 redirects to a location with pushes configured. Found by Coverity (CID 1429156).

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


cat << END >> $NGX_AUTO_CONFIG_H

#ifndef $have
#define $have  $value
#endif

END