Mp4: remove useless leading stsc entry in result mp4. The fix removes useless stsc entry in result mp4. If start_sample == n then current stsc entry should be skipped and the result stsc should start with the next entry. The reason for that is start_sample starts from 0, not 1.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


cat << END >> $NGX_AUTO_HEADERS_H

#ifndef $have
#define $have  1
#endif

END