Prefix path when displaying thin archives.

Patch by Mark Santaniello.

llvm-svn: 288615
diff --git a/llvm/tools/llvm-ar/llvm-ar.cpp b/llvm/tools/llvm-ar/llvm-ar.cpp
index 004ef01..26f8d5b 100644
--- a/llvm/tools/llvm-ar/llvm-ar.cpp
+++ b/llvm/tools/llvm-ar/llvm-ar.cpp
@@ -359,6 +359,11 @@
     outs() << ' ' << ModTimeOrErr.get();
     outs() << ' ';
   }
+
+  if (C.getParent()->isThin()) {
+    outs() << sys::path::parent_path(ArchiveName);
+    outs() << sys::path::get_separator();
+  }
   outs() << Name << "\n";
 }