One more place to work around missing std::underlying_type for GCC 4.6

Change-Id: I46225e30f6326e0af5a8ac3bebe9847f4dbe50d0

include/formula/tokenarray.hxx

@@ -23,6 +23,8 @@
 #include <com/sun/star/sheet/FormulaToken.hpp>
 #include <formula/token.hxx>
 #include <formula/ExternalReferenceHelper.hxx>
+#include <o3tl/underlying_type.hxx>
+
 #include <limits.h>
 #include <type_traits>
 #include <unordered_set>
@@ -90,7 +92,7 @@ public:
     inline  bool    isRewriteNeeded( OpCode eOp ) const;
 };
 
-typedef std::unordered_set<OpCode, std::hash<std::underlying_type<OpCode>::type> > unordered_opcode_set;
+typedef std::unordered_set<OpCode, std::hash<o3tl::underlying_type<OpCode>::type> > unordered_opcode_set;
 
 class FORMULA_DLLPUBLIC FormulaTokenArray
 {

include/o3tl/underlying_type.hxx

+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef INCLUDED_O3TL_UNDERLYING_TYPE_HXX
+#define INCLUDED_O3TL_UNDERLYING_TYPE_HXX
+
+#include <sal/config.h>
+
+#include <type_traits>
+
+namespace o3tl {
+
+template<typename T> struct underlying_type {
+#if defined __GNUC__ && __GNUC__ == 4 && __GNUC_MINOR__ <= 7 && \
+        !defined __clang__
+    typedef int type;
+#else
+    typedef typename std::underlying_type<T>::type type;
+#endif
+};
+
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */