rem: seq->alloc = 1; seq->lines = (struct line *) xmalloc (seq->alloc * sizeof (struct line));
add: seq->alloc = 0; seq->lines = NULL;
context: initseq (struct seq *seq){  seq->count = 0;  seq->alloc = 1;  seq->lines = (struct line *) xmalloc (seq->alloc * sizeof (struct line));}