#[repr(C)]pub struct Multiboot{    pub flags: u32,    pub mem_lower: u32,    pub mem_higher: u32,    pub boot_device: [u8; 4],    pub cmdline: u32,    pub mods_count: u32,    pub mods_addr: u32,    pub syms: [u32; 4],    pub mmap_length: u32,    pub mmap_addr: u32,    pub drives_length: u32,    pub drives_addr: u32,    pub config_table: u32,    pub boot_loader_name: u32,    pub apm_table: u32,    pub vbe_control_info: u32,    pub vbe_mode_info: u32,    pub vbe_mode: u32,    pub vbe_interface_seg: u32,    pub vbe_interface_off: u32,    pub vbe_interface_len: u32,} extern "C"{    pub static multibootsig : u32;    pub static multibootptr : &'static Multiboot;}