anchor.diff:     #:o-sync
      #:o-nofollow
      #:o-async
  +   #:o-cloexec
   
      ;; Lseek()
      #:seek-set
  
positive.code:    ;; Signals
     #:kill
     #:sigaction
  
     ;; Time
     #:usleep
  
negative.code:    #+linux #:sigrtmin
     #+linux #:sigrtmax
  
     ;; waitpid()
     #:wnohang
     #:wuntraced
     #:wcontinued
  
     ;; Sigaction()
     #:sig-ign
     #:sig-dfl
     #:sa-nocldstop
     #:sa-nocldwait
     #:sa-nodefer
     #:sa-onstack
     #:sa-resethand
     #:sa-restart
     #:sa-siginfo
  
     ;; Fcntl()
     #:f-dupfd
  