Fix to avoid warning. Also add header, and lincense information.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@154928 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/BuiltinsHexagon.def b/include/clang/Basic/BuiltinsHexagon.def
index c57f9b9..ffe03ec 100644
--- a/include/clang/Basic/BuiltinsHexagon.def
+++ b/include/clang/Basic/BuiltinsHexagon.def
@@ -1,3 +1,19 @@
+//===-- BuiltinsHexagon.def - Hexagon Builtin function database --*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the Hexagon-specific builtin function database.  Users of
+// this file must define the BUILTIN macro to make use of this information.
+//
+//===----------------------------------------------------------------------===//
+
+// The format of this database matches clang/Basic/Builtins.def.
+
 
 // This one below is not generated from the autogenerated iset.py.
 // So make sure you donot overwrite this one.