ISSET
#define ISSET(A, N) ((A)[(N)/BITS_PER_MAP] & (1<<((N)%BITS_PER_MAP)))
#define ISSET(opt) (sp->fts_options & (opt))
#undef ISSET
#define ISSET(v, n) ((v)[n])
#define ISSET(v, n) (((v) & ((unsigned long)1 << (n))) != 0)