[clang] [z/OS][Clang] Reland Add wrapper headers to avoid macro name conflicts (#204472) (PR #207420)

[Sean Perry via cfe-commits]

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@@ -0,0 +1 @@
+#define __cs 1
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perry-ca wrote:

This header isn't used in the test case and can be removed.

https://github.com/llvm/llvm-project/pull/207420