Better documentation about which libraries are linked by default by the rust compiler

[weiznich]

Location

Release notes, possibly the reference, not sure where else

Summary

There is currently no documentation about which system libraries are linked by rustc via the standard library and which of these libraries are guaranteed to be linked in the future. This was noticed while reporting #139352 and should likely be fixed before that change is stable.

Ideally there would be a list/table of linked libraries per target for at least tier 1 targets that contains all linked system libraries and also clarify which of these libraries are guaranteed to be linked in the future. (If none are guaranteed to be linked that's also fine, if that's stated explicitly). In addition it would be great to include documentation on how to test if your code relies on such not-guaranteed linkage. For windows that seems to be the command described by @ChrisDenton here. I'm not sure if similar commands exist for other platforms?

[ChrisDenton]

--print native-static-libs can be used to list the current libraries that will be linked. E.g.:

rustc empty.rs --print native-static-libs --crate-type staticlib

Currently on Windows it is: kernel32.lib, ntdll.lib, userenv.lib, ws2_32.lib and dbghelp.lib.

---

When compiling C/C++ libraries perhaps the easier thing to do would be to test them in a minimal C/C++ program. If it can't link without specifying extra libraries than it may break in Rust too.