Unweaken vtables as per http://llvm.org/docs/CodingStandards.html#ll_virtual_anch

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146959 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/PostOrderCFGView.cpp b/lib/Analysis/PostOrderCFGView.cpp
index 311423f..cfd66f7 100644
--- a/lib/Analysis/PostOrderCFGView.cpp
+++ b/lib/Analysis/PostOrderCFGView.cpp
@@ -15,6 +15,8 @@
 
 using namespace clang;
 
+void PostOrderCFGView::anchor() { }
+
 PostOrderCFGView::PostOrderCFGView(const CFG *cfg) {
   Blocks.reserve(cfg->getNumBlockIDs());
   CFGBlockSet BSet(cfg);