Update for LLVM API change

llvm-svn: 222303
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 5d25ed7..d459e4b 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -884,7 +884,7 @@
       }
 
       A->claim();
-      if (ArchNames.insert(A->getValue()))
+      if (ArchNames.insert(A->getValue()).second)
         Archs.push_back(A->getValue());
     }
   }