Add vtable anchor to classes.

llvm-svn: 350142
diff --git a/llvm/lib/Support/FormatVariadic.cpp b/llvm/lib/Support/FormatVariadic.cpp
index 6dd133e..1f3505d 100644
--- a/llvm/lib/Support/FormatVariadic.cpp
+++ b/llvm/lib/Support/FormatVariadic.cpp
@@ -152,3 +152,5 @@
   }
   return Replacements;
 }
+
+void detail::format_adapter::anchor() { }