Fix a comment.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@187502 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index eb3c4f8..7eccbb5 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -2718,7 +2718,7 @@
   Args.AddLastArg(CmdArgs, options::OPT_w);
 
   // Handle -{std, ansi, trigraphs} -- take the last of -{std, ansi}
-  // (-ansi is equivalent to -std=c89).
+  // (-ansi is equivalent to -std=c89 or -std=c++98).
   //
   // If a std is supplied, only add -trigraphs if it follows the
   // option.