Method enqueue

src/ugrep.cpp:2079–2082

add a sentinel NONE job to the queue

    // add a sentinel NONE job to the queue
    void enqueue()
    {
      enqueue("", Entry::UNDEFINED_COST, Job::NONE);
    }

    // add a job to the queue
    void enqueue(const char *pathname, uint16_t cost, size_t slot)