Decompresses data using lzss. allegro game programming library.
#include <allegro.h>
int lzss_read(PACKFILE *file, LZSS_UNPACK_DATA *dat, int s, unsigned char *buf);
Unpacks from `dat' into `buf', until either EOF is reached or `s' bytes have been extracted from `file'.
Returns the number of bytes added to the buffer `buf'.
free_lzss_unpack_data(3alleg4)