message: Don't use logfile FD if it's -1
diff: @@ -454,6 +454,7 @@ void ReleaseFDAfterFork()
  {
  // we do NOT release the shared lock here, since the file descriptor is shared so we'd be
  // releasing the parent process's lock. Just close our file descriptor
  + if(logfileFD >= 0)
  close(logfileFD);
  }
  @@ -474,13 +475,13 @@ bool logfile_open(const char *filename)
  void logfile_append(const char *msg, size_t length)
  {
  - if(logfileFD)
  + if(logfileFD >= 0)
  write(logfileFD, msg, (unsigned int)length);
  }
  void logfile_close(const char *filename)
  {
  - if(logfileFD)
  + if(logfileFD >= 0)
  {
  // release our shared lock
  int err = flock(logfileFD, LOCK_UN | LOCK_NB);
  