I was looking into this a bit the other day, I think this is a problem in the linker, where we don't currently link with a module if there is no wasm import, and as we are not using anything from the module we dont have any imports to it.

I think the best way to fix this would be to read the imports from the cmi, or if we want an approach that makes the intermediate wasm slightly more correct, we could import the _start function and call it in the main modules _start function, though its important to keep in mind if we use the second approach that we cant just reoutput the _start section we would need to deduplicate and properly order the _start calls. I am a fan of method two as it works better with dynamic linking which we no longer support but its cool to leave the option open.