[gPXE] environment variable expansion in 'filename'?

[Miller, Shao]

Good day Jarrod,

How about putting 'http://central_server/some_script.gpxe' in as the
filename?  Then some_script.gpxe could go:

#!gpxe
chain http://${next-server}/filename

The ${} expansion is only applied for scripts and CLI at this time.

If you are handing out a different next-server option, why is it more
difficult to hand out an explicit filename option including the local
server?

- Shao Miller