P0035R4: add std::align_val_t overloads of operator new/delete in C++17 mode.

llvm-svn: 282800
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 0866e3a..253fab2 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -4363,9 +4363,10 @@
 
   // Build a record containing some declaration references.
   RecordData SemaDeclRefs;
-  if (SemaRef.StdNamespace || SemaRef.StdBadAlloc) {
+  if (SemaRef.StdNamespace || SemaRef.StdBadAlloc || SemaRef.StdAlignValT) {
     AddDeclRef(SemaRef.getStdNamespace(), SemaDeclRefs);
     AddDeclRef(SemaRef.getStdBadAlloc(), SemaDeclRefs);
+    AddDeclRef(SemaRef.getStdAlignValT(), SemaDeclRefs);
   }
 
   RecordData CUDASpecialDeclRefs;