therefore fallback to stat() if dirent.d_type is not set,
this fixes slash after directory name in ngx_http_autoindex_module;
the issue has been introduced in r2235
*) introduce postpone_gzipping directive
*) disable postponed gzipping by default
The r2411 commit caused hangings up on large SSIed responses
as SSI cleared buf->recycled bit on copy of recycled buf parts
