[syslinux] [0/1] [gfxboot] align buffer used to read data from disk to a 512 byte boundary

[Christophe Fergeau]

Hi,

In Mandriva, we've been hit by a bug on specific machines where gfxboot 
would fail to load with:

gfxboot:
isolinux: Disk error 09, AX = 424F, drive FE

A contributor lent us one such machine, and after some debugging, I 
realized that the buffer used by gfxboot to read data from the disk 
isn't aligned as the COM API mandates it (512 bytes boundary). Aligning 
it to a dword boundary is enough to fix the problem, but the coming 
patch attempts to align it to 512 bytes boundary to do what the COM API 
expects. However, I have no idea how the start of the .data section is 
aligned in a COM module, so I don't know if it's enough to use align 512 
(as the upcoming patch does) or if something more complicated has to be 
done. Let me know if this should be done differently :)

Thanks,

Christophe