The three ways to build a binary image

Link it all into a big object file
This is what we were doing at the beginning
It allows for a platform-independent    bigobj.lds   intermediate script
But it shows its limits when the code base increases
I had to abandon this to implement BUG()

Build it all and create a library file (.a)
This is the current approach
We build-test all of the code
Well, excluding alternatives for other architectures
Object files that are not picked are just ignored
If a weak symbol exists, no strong symbol is looked for
This is useful in a multi-application environment
In our code base, we build several .bin files

Only build what you need to run
You lack build-test for all code, but you save compiler time
Useful in big projects that create a single binary
Examples: Linux, u-boot, barebox, buildroot