[clang] [llvm] Enable fexec-charset option (PR #138895)

[Richard Smith via llvm-commits]

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@@ -491,6 +491,9 @@ class Triple {
   /// For example, "fooos1.2.3" would return "1.2.3".
   StringRef getEnvironmentVersionString() const;
 
+  /// getSystemCharset - Get the system charset of the triple.
+  StringRef getSystemCharset() const;
+
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zygoloid wrote:

Would it make sense to include "Narrow" in the name here too? (This applies to `'x'` and `"x"`, not to the wide character set used by `L'x'` or `L"x"`.)

https://github.com/llvm/llvm-project/pull/138895