ngx_http_proxy_add_variables  112 http/modules/ngx_http_proxy_module.c static ngx_int_t ngx_http_proxy_add_variables(ngx_conf_t *cf);
ngx_http_proxy_add_variables  451 http/modules/ngx_http_proxy_module.c     ngx_http_proxy_add_variables,          /* preconfiguration */