Is bindgen object merging necessary?

In https://github.com/bazelbuild/rules_rust/pull/2361 we have added logic (that became the default since then) to merge object files of `cc_lib` into the `rlib` produced by bindgen rules. The problem this is solving is related to some annoying ordering errors when using both Bazel and Cargo on a project using bindgen in a build script.

I can't say I understand exactly what the problem is, but it has bitten us recently (hence https://github.com/bazelbuild/rules_rust/pull/2959). But intuitively, if the problem is related to link ordering when build scripts are involved, maybe a better fix would be to propagate CcInfo from build scripts?

Any information/repro instructions of the original problem will be super useful.

@UebelAndre @krasimirgg