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

[Fangrui Song via cfe-commits]

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@@ -2426,6 +2432,31 @@ void Generic_GCC::GCCInstallationDetector::AddDefaultGCCPrefixes(
   using std::begin;
   using std::end;
 
+  if (TargetTriple.isOSHaiku()) {
+    static const char *const HaikuLibDirs[] = {"/lib"};
+    static const char *const HaikuAArch64Triples[] = {"aarch64-unknown-haiku"};
+    static const char *const HaikuRISCV64Triples[] = {"riscv64-unknown-haiku"};
+    static const char *const HaikuX86Triples[] = {"i586-unknown-haiku"};
+    static const char *const HaikuX86_64Triples[] = {"x86_64-unknown-haiku"};
+    LibDirs.append(begin(HaikuLibDirs), end(HaikuLibDirs));
+    switch (TargetTriple.getArch()) {
+    case llvm::Triple::aarch64:
+      TripleAliases.append(begin(HaikuAArch64Triples), end(HaikuAArch64Triples));
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MaskRay wrote:

If `--target=` is correct, we don't need any `TripleAliases` ?

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