[clang] [llvm] [SystemZ][z/OS] This change adds support for the PPA2 section in zOS (PR #68926)

[Ulrich Weigand via cfe-commits]

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@@ -90,6 +90,7 @@ LANGOPT(C23               , 1, 0, "C23")
 LANGOPT(MSVCCompat        , 1, 0, "Microsoft Visual C++ full compatibility mode")
 LANGOPT(Kernel            , 1, 0, "Kernel mode")
 LANGOPT(MicrosoftExt      , 1, 0, "Microsoft C++ extensions")
+LANGOPT(ASCIICharMode     , 1, 1, "z/OS Language Environment Character mode")
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uweigand wrote:

This doesn't appear to do anything except for setting the PPA flag.   Is this correct?  If the implementation is simply incomplete / not present yet, I don't think we should add this flag now - rather, we should have the PPA flag reflect the default and update this once full support for ASCII mode is merged.

https://github.com/llvm/llvm-project/pull/68926