Upstream: subrequest_in_memory fix. With previous code only part of u->buffer might be emptied in case of special responses, resulting in partial responses seen by SSI set in case of simple protocols, or spurious errors like "upstream sent invalid chunked response" in case of complex ones.

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


cat << END >> $NGX_AUTO_CONFIG_H

#ifndef $have
#define $have  1
#endif

END