_kern_fcntl
extern status_t _kern_fcntl(int fd, int op, size_t argument);
return (kernelFD ? _kern_fcntl : _user_fcntl)(fd, F_SETFL, argument);
status_t error = _kern_fcntl(fd, op, argument);
fssh_status_t _kern_fcntl(int fd, int op, uint32_t argument);