anchor.diff:      ++ optional moreheaders "--add-module=${moreheaders-ext}"
       ++ optional echo "--add-module=${echo-ext}"
       ++ optional ngx_lua "--add-module=${develkit-ext} --add-module=${lua-ext}"
  +    ++ optional set_misc "--add-module=${set-misc-ext}"
       ++ optional (elem stdenv.system (with platforms; linux ++ freebsd)) "--with-file-aio";
   
   
  
positive.code:     sha256 = "0r07q1n3nvi7m3l8zk7nfk0z9kjhqknav61ys9lshh2ylsmz1lf4";
    };
  
  in
  
  stdenv.mkDerivation rec {
  
negative.code: , syslog ? false
  , moreheaders ? false
  , echo ? false
  , ngx_lua ? false
  , set_misc ? false
  }:
  
  with stdenv.lib;
  
  