merge r2972, r2994, r3133, r3142, r3143, r3174, r3175, r3176: various perl fixes: *) fix ngx_http_send_special() for subrequests handled by perl *) allow perl "sub{..." *) restore environ, this fixes segfault on reconfiguration failure when perl module creates new environment *) optimize error handling *) use ngx_conf_set_str_array_slot() for perl_require *) allow several perl_modules

--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -2898,7 +2898,7 @@ ngx_http_upstream_finalize_request(ngx_h
 
     r->connection->log->action = "sending to client";
 
-    if (rc == 0 && r == r->main && !r->post_action) {
+    if (rc == 0) {
         rc = ngx_http_send_special(r, NGX_HTTP_LAST);
     }