Joseph,
please read the link in @Wrathchild's post from top to bottom. In chapter 4.1 there is one linker config file called "atari-cart.cfg", which is exactly what you want (create a cartridge image).
In general, considering your other posts, it appears to me that you are pursuing solutions for problems which don't exist (at least for the rest of us). And you seem to be immune against good advice.
I guess the best way forward would be to find a small, simple problem where you could implement a solution.
regards,
chris