[clang] [Driver] Implement ToolChain on Haiku (PR #66038)

[Fangrui Song via cfe-commits]

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@@ -15,30 +15,53 @@
 
 namespace clang {
 namespace driver {
+namespace tools {
+
+/// Directly call GNU Binutils assembler and linker
+namespace haiku {
+class LLVM_LIBRARY_VISIBILITY Linker : public Tool {
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MaskRay wrote:

`class LLVM_LIBRARY_VISIBILITY Linker final : public Tool`. This should improve compiler devirtualization.

https://github.com/llvm/llvm-project/pull/66038