PHP 5.4 - Fatal error: Cannot pass parameter 2 by reference in dmemcache_get_multi()

Running with PHP 5.4 and Memcached extension, calling dmemcache_get_multi() produces the error message:
"Fatal error: Cannot pass parameter 2 by reference"

This happens because of:

  // Line 138
  $results = $mc->getMulti($full_keys,NULL,NULL);

The second parameter of getMulti() is passed by reference, so you can't pass NULL.

Attached is a patch that fixes it by not sending parameters 2+3 at all, since the module doesn't use the CAS tokens feature.