ACPI does not need to be recompiled, it is already compiled as a kernel module.
grep -i acpi /usr/src/linux/.config
You just need to load these modules, same as any kernel module:
modprobe ac
modprobe battery
modprobe thermal
modprobe processor
modprobe fan
etc etc
If you want this done automatically, and you use a HD install, then I suppose:
echo '/sbin/modprobe ac' >> /etc/rc.d/rc.modules
echo '/sbin/modprobe battery' >> /etc/rc.d/rc.modules
(and the same for the other ACPI modules I mention above)
should do it.
If you use the live cd, then add the modprobe commands to rc.local and make it a .mo.
There, that wasn't so hard now, was it?