fchmodat
if (fchmodat(AT_FDCWD, p->fts_accpath, newmode, atflag) == -1
r = fchmodat(AT_FDCWD, name,
int fchmodat(int, const char *, mode_t, int);
int fchmodat(int, const char *, mode_t, int);
struct fchmodat_args fchmodat;