[clang] [SystemZ][z/OS] Add visibility features for z/OS (eg. _Export, pragma export) (PR #111035)

[Aaron Ballman via cfe-commits]

================
@@ -2002,6 +2014,9 @@ class Declarator {
   /// this declarator as a parameter pack.
   SourceLocation EllipsisLoc;
 
+  /// The source location of the _Export keyword on this declarator
----------------
AaronBallman wrote:

```suggestion
  /// The source location of the _Export keyword on this declarator.
```

https://github.com/llvm/llvm-project/pull/111035