[syslinux] Support DHCP sname field in PXELINUX

[Chris Adams]

Once upon a time, H. Peter Anvin <hpa at zytor.com> said:
> I mean, the right thing to do is probably, in order:
> 
> 1. Use siaddr
> 2. Use sname
> 3. Use option 54.

I've done some more digging, and it appears that the PXE BIOS in the
computers I'm testing with do not look at the sname field.  They do look
at option 54 ("server-identifier" in Juniper JUNOS).  It would probably
be more "correct" then to duplicate that and use (siaddr, option 54) and
ignore sname (since that is what it looks like the PXE BIOS does).

-- 
Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.