[lld] [lld][ELF] Support LLVM repository and LLVM revision information (PR #97323)

[Fangrui Song via llvm-commits]

MaskRay wrote:

The description (which will be used as the default commit message when "Squash and merge" is clicked) is probably about 
`LLVM_APPEND_VC_REV=on`. 

> I'd also consider removing the parenthesis around the compatible with GNU linkers part in the ELF driver so we end up with:

In the `LLVM_APPEND_VC_REV=off` configuration,

```
% fld.lld --version
LLD 19.0.0 compatible with GNU linkers
```

Without parentheses, "compatible ..." might be parsed as part of the version string.

Should parentheses be added back? We could also use a leading comma or something else, but lld/MinGW/Driver.cpp should be updated as well for consistency.

https://github.com/llvm/llvm-project/pull/97323