cond_width
sz += cond_width(p, uc, &skip);
sz += cond_width(p, ' ', &skip);
sz += cond_width(p, '-', &skip);
static size_t cond_width(const struct termp *, int, int *);
sz += cond_width(p, *cp++, &skip);
sz += cond_width(p, uc, &skip);