rem: (tchar **) calloc((unsigned) (blklen(v) + 1),
add: (tchar **)xcalloc((unsigned)(blklen(v) + 1),
context: copyblk(tchar **v){	tchar **nv =		(tchar **) calloc((unsigned) (blklen(v) + 1),				sizeof (tchar **));	return (blkcpy(nv, v));}