Merge of r4698: X-Forwarded-For conditionals. Fixed compile-time conditionals used to detect if X-Forwarded-For support is needed. Note: compatibility shims were added during merge to avoid possible breakage of 3rd party modules. At least cache purge module was broken by the original commit, as it used to rely on NGX_HTTP_PROXY define.

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


cat << END >> $NGX_AUTO_HEADERS_H

#ifndef $have
#define $have  1
#endif

END