One issue here is that while we have the infrastructure (linux/windows) to cross-compile for mobile platforms, we don’t have anything setup to test if the compiled binary actually works. I don’t have any experience in this area.
Actually running the binary would be much more involved. Since its cross-compilation there’s nothing to run it on… (And to make it even more complicated, you can’t just run a ‘hello world’ exe on mobile anyway without it being a proper app.)
Cross-compilation in general is going to have this issue. For example, if you added mingw support on linux (gcc that compiles to windows).
In general, if you can get an executable or shared lib to link you’re 95% of the way there. It may be that this is “good enough”.