/usr/include/sys/ioctl.h/usr/include/sys/limits.h/usr/include/errno.h
/usr/include/sys/ioctl.hsurrounded by
#ifndef _IOCTL_H
#define _IOCTL_H
...
#endif
to prevent multiple includes.
/usr/include/sys/ioctl.h/usr/include/sys/limits.h/usr/include/errno.h