blkcpy
Char **blkcpy(Char **, Char **);
(void) blkcpy(nfbuf, fbuf);
(void) blkcpy(fbuf, &fbuf[sb]);
(void) blkcpy(blkend(up), vp);
(void) blkcpy(wp, up);
(void) blkcpy(v, u);
return (blkcpy(nv, v));