C++1y deduced return types: when we deduce a return type for a function which
we loaded from PCH, if we're building another PCH, create an update record to
patch the return type of the earlier declaration.

llvm-svn: 181659
diff --git a/clang/lib/Serialization/ASTCommon.h b/clang/lib/Serialization/ASTCommon.h
index 76ef904..fa3ef58 100644
--- a/clang/lib/Serialization/ASTCommon.h
+++ b/clang/lib/Serialization/ASTCommon.h
@@ -25,7 +25,8 @@
   UPD_CXX_ADDED_IMPLICIT_MEMBER,
   UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION,
   UPD_CXX_ADDED_ANONYMOUS_NAMESPACE,
-  UPD_CXX_INSTANTIATED_STATIC_DATA_MEMBER
+  UPD_CXX_INSTANTIATED_STATIC_DATA_MEMBER,
+  UPD_CXX_DEDUCED_RETURN_TYPE
 };
 
 TypeIdx TypeIdxFromBuiltin(const BuiltinType *BT);