vline_set
extern int vline_set(const cchar_t *, int);
#define mvvline_set(y,x,cp,n) (move(y,x)?ERR:vline_set(cp,n))
extern int vline_set(const cchar_t *, int);
(move(y, x) ? (cp, n, ERR) : vline_set(cp, n))