Upstream keepalive module.
diff --git a/auto/options b/auto/options
index f30917c..2019498 100644
--- a/auto/options
+++ b/auto/options
@@ -95,6 +95,7 @@
 HTTP_MP4=NO
 HTTP_GZIP_STATIC=NO
 HTTP_UPSTREAM_IP_HASH=YES
+HTTP_UPSTREAM_KEEPALIVE=YES
 
 # STUB
 HTTP_STUB_STATUS=NO
@@ -231,6 +232,7 @@
         --without-http_empty_gif_module) HTTP_EMPTY_GIF=NO          ;;
         --without-http_browser_module)   HTTP_BROWSER=NO            ;;
         --without-http_upstream_ip_hash_module) HTTP_UPSTREAM_IP_HASH=NO ;;
+        --without-http_upstream_keepalive_module) HTTP_UPSTREAM_KEEPALIVE=NO ;;
 
         --with-http_perl_module)         HTTP_PERL=YES              ;;
         --with-perl_modules_path=*)      NGX_PERL_MODULES="$value"  ;;