So, now we have all the fs converted, and the rest is to make it better and more simple

the others Syslinux derivative disabled for now

it works, but it broke somewhere; it can't display the menu correctly.

The two functions are converted to C.
And for another thing, I find that I haven't included the load_config.c file before(my fault),
so added it here.

and fixed some errors.

extract the sector read functions to disk.c, and add SECTOR_SHIFT, SECTOR_SIZE
stuff in the disk.h as asked by hpa.

Add a new function read_sectors, the only function will call getlinsec, so we can read sectors easily by calling read_sectors function

and removed the itao function as the printf function works well now