[syslinux] Passing TFTP server IP address via pxelinux config file

[conradl at argontechnology.com]

It is possible to pass the IP address of a TFTP server to pxelinux config
file.

Scenario:

I'm trying to network boot a thinstation image file
(http://thinstation.sourceforge.net) via PXE.  However, I'm using a DSL
router as my DHCP server and Argon CMS (http://www.argontechnology.com/cms)
as my PXE/TFTP server.   When it initrd is execute and the network adapter
is detected and TCP/IP stack is loaded, it tries to TFTP down the
thinstation.conf file from the DHCP server.     I need to force  the image
to get the thinstation.conf file from the PXE server.

Thanx.