Do zero initialization without memset
Do zero initialization without memset

This minimizes the diff to upstream.

mstorsjo/vo-aacenc,Distrotech/vo-aacenc,Distrotech/vo-aacenc,Distrotech/vo-aacenc,mstorsjo/vo-aacenc,vamsirajendra/vo-aacenc,vamsirajendra/vo-aacenc