getopt: fix null pointer arithmetic ub

[musl] / src / linux / open_by_handle_at.c

#define _GNU_SOURCE
#include <fcntl.h>
#include "syscall.h"

int open_by_handle_at(int mount_fd, struct file_handle *handle, int flags)
{
        return syscall(SYS_open_by_handle_at, mount_fd, handle, flags);
}