Auto merge of #161260 - weihanglo:cc-1.4.3, r=Kobzol

chore: bump to cc@1.4.3 for rustc_llvm and library



### What is this?

Old cc-rs derives this from the `-Clto` rustflag on its own.
`cc@1.2.39` starts gating that behind `-Clinker-plugin-lto`,
which bootstrap doesn't pass.
Therefore,
we need to pass this flag explicitly to keep LTO mode

Previous efforts:

* https://github.com/rust-lang/rust/pull/146186
* https://github.com/rust-lang/rust/pull/155438

I personally want this because of cc 1.3.0+ has the support of Cargo `-Ztrim-paths`,
which helps what I am experimenting in <https://github.com/rust-lang/rust/pull/161049>.

### How to review

Commit by commit. 

To keep commits bisect-able,
I added the first commit without cc bump.
clang should be fine with duplicate `-flto` flags.

One thing I am not certain is whether we should probe `-flto` flag in this case,
or just make this fail if `-flto` isn't supported.
(I assume `-flto` is quote widely supported)

r? Kobzol

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🤖 **LLM disclosure:** I used LLM for the experiment of <https://github.com/rust-lang/rust/pull/161049>, but not the bootstrap LTO change in this PR.