Fixed "zero size buf in output" alerts. If a request had an empty request body (with Content-Length: 0), and there were preread data available (e.g., due to a pipelined request in the buffer), the "zero size buf in output" alert might be logged while proxying the request to an upstream. Similar alerts appeared with client_body_in_file_only if a request had an empty request body.

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


cat << END >> $NGX_AUTO_CONFIG_H

#ifndef $have
#define $have  1
#endif

END