쓰레드와 프로세스로 유명한 철학자 문제를 구현해보는 과제
memset, printf, malloc, free, write, fork, kill,
exit, pthread_create, pthread_detach, pthread_join,
usleep, gettimeofday, waitpid, sem_open, sem_close,
sem_post, sem_wait, sem_unlink, pthread_create,
pthread_detach, pthread_join, pthread_mutex_init,
pthread_mutex_destroy, pthread_mutex_lock,
pthread_mutex_unlock