Make format string 64 bit safe.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143870 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/VTableBuilder.cpp b/lib/AST/VTableBuilder.cpp
index 7765817..f819f67 100644
--- a/lib/AST/VTableBuilder.cpp
+++ b/lib/AST/VTableBuilder.cpp
@@ -2136,7 +2136,7 @@
       uint64_t VTableIndex = I->first;
       const std::string &MethodName = I->second;
 
-      Out << llvm::format(" %4u | ", VTableIndex) << MethodName << '\n';
+      Out << llvm::format(" %4"PRIu64" | ", VTableIndex) << MethodName << '\n';
     }
   }