[clang] Frontend: sink vendor definitions from Basic to Frontend (PR #80364)

[Saleem Abdulrasool via cfe-commits]

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@@ -804,6 +804,11 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     }
   }
 
+  if (TI.getTriple().getVendor() == Triple::AMD)
+    Builder.defineMacro("__AMD__");
+  if (TI.getTriple().getVendor() == Triple::Apple)
+    Builder.defineMacro("__APPLE__");
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compnerd wrote:

Yes, and something that I think that is desirable in the context of Swift as well (where we are looking at some of the embedded system usage where the target triple may be something like `arm64-apple-none-macho`).

https://github.com/llvm/llvm-project/pull/80364