Added c++ mode selector to head of SelectionDAGBuilder.h so editors open it in c++ mode instead of c mode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185348 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index 90d95c0..ef73c00 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -1,4 +1,4 @@
-//===-- SelectionDAGBuilder.h - Selection-DAG building --------------------===//
+//===-- SelectionDAGBuilder.h - Selection-DAG building --------*- c++ -*---===//
 //
 //                     The LLVM Compiler Infrastructure
 //