How to access kernel config from application?

[yakoda]

I use different configurations of the same kernel (2.4).

How can I add an information (e.g. string or int) to my kernel which my user space application will be able to get?
I tried to set EXTRAVERSION in the main Makefile of the kernel. I get it back using uname(). It works, but then my kernel module (char driver) is not able to be loaded in all the configurations (insmod fails with error: "kernel-module version mismatch"). I don't want to handle a different binary of my kernel module for each kernel config change.

I understand that EXTRAVERSION is not made for the use I did. What should I use instead to store my private config tracking?

Thanks!