ok i worked that one out :
for 2.4.x kernel
just symlink /lib/modules/2.4.18-rmk7-pxa3-embedix/build to the location of your kernel-source's "root" 'linux' directory .
ps if you get to the part in your module build and it says it cant find modversions.h as i did,
you need to go back and recompile your kernel enabling module version support options
now when you issue make dep it will make this file