[llvm] [z/OS] Add z/OS archive reading support (PR #187110)

[James Henderson via llvm-commits]

================
@@ -1448,3 +1602,73 @@ BigArchive::BigArchive(MemoryBufferRef Source, Error &Err)
   setFirstRegular(*I);
   Err = Error::success();
 }
+
+ZOSArchive::ZOSArchive(MemoryBufferRef Source, Error &Err)
+    : Archive(Source, Err) {
+  ErrorAsOutParameter ErrAsOutParam(&Err);
+
+  // Get the special members.
+  child_iterator I = child_begin(Err, false);
+  if (Err)
----------------
jh7370 wrote:

Test case showing that this error is checked-for correctly?

https://github.com/llvm/llvm-project/pull/187110