[AArch64 ACLE] Allow to define poly64_t as 'unsigned long long' on LLP64 system.

This fixes PR23414 as well.

llvm-svn: 237348
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 6e55655..7acaf09 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -2311,6 +2311,7 @@
       EltName = "Poly16";
       break;
     case BuiltinType::ULong:
+    case BuiltinType::ULongLong:
       EltName = "Poly64";
       break;
     default: