Override ReadArrayCookie in MicrosoftCXXABI and explicitly mark it unimplemented

lib/CodeGen/MicrosoftCXXABI.cpp

Index: lib/CodeGen/MicrosoftCXXABI.cpp
===================================================================
--- lib/CodeGen/MicrosoftCXXABI.cpp	(revision 153329)
+++ lib/CodeGen/MicrosoftCXXABI.cpp	(working copy)
@@ -78,6 +78,12 @@
   //     delete[] p;
   //   }
   // Whereas it prints "104" and "104" if you give A a destructor.
+  void ReadArrayCookie(CodeGenFunction &CGF, llvm::Value *Ptr,
+                       const CXXDeleteExpr *expr,
+                       QualType ElementType, llvm::Value *&NumElements,
+                       llvm::Value *&AllocPtr, CharUnits &CookieSize) {
+    llvm_unreachable("Don't know how to handle array cookies yet!");
+  }
 };
 
 }