In a PR to emit warnings on misuse of `--print native-static-libs`,
we did not consider the matter of composing parts of build systems.
If you are not directly invoking rustc, it can be difficult to know
when you will in fact compile a staticlib, so making sure everyone
uses `--print native-static-lib` correctly can be just a nuisance.
This reverts the following commits:
- f66787a08d
- 72a9219e82
- 98bb597c05
- c59b70841c
Next cycle we can reland a slightly more narrowly focused variant or one
that focuses on `--emit` instead of `--print native-static-libs`.
But in its current state, I am not sure the warning is very useful.
7b29a5d282