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

[Sean Perry via cfe-commits]

================
@@ -0,0 +1,19 @@
+/*===----------------------------- locale.h ---------------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __ZOS_WRAPPERS_LOCALE_H
+#define __ZOS_WRAPPERS_LOCALE_H
+#if defined(__MVS__)
----------------
perry-ca wrote:

I believe the better/safer way to do this is:
```suggestion
#if __has_include_next(<locale.h>)
```
Can you try that out.  Thanks

https://github.com/llvm/llvm-project/pull/204472