equiv
static void equiv(struct line *, int, struct line *, int, int *);
equiv(sfile[0], slen[0], sfile[1], slen[1], member);
const char *equiv;
if (s->set != s->equiv) {
s->equiv[0] = backslash(s);
s->equiv[0] = ch;
s->set = s->equiv;
int equiv[2]; /* equivalence set */
s->equiv[0] = 0;
s->equiv[1] = OOBCH;
if (s->set != NULL && s->set != s->equiv) {