[clang] [FatLTO] Detect LLD linker more reliably (PR #128285)

[Fangrui Song via cfe-commits]

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@@ -862,13 +862,12 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
   const llvm::Triple &Triple = ToolChain.getTriple();
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MaskRay wrote:

This change would be desired as -fuse-ld= is better than --ld-path=. However, some users customize CLANG_DEFAULT_LINKER or hard code lld. They have no -fuse-ld= but still use lld....

https://github.com/llvm/llvm-project/pull/128285