From b6300d97ff6594cd69dc413eb87295a1be50bb98 Mon Sep 17 00:00:00 2001
From: John Wellbelove <john.wellbelove@asterconsulting.co.uk>
Date: Wed, 7 May 2025 07:24:39 +0100
Subject: [PATCH] C++03 compatibiity to to_underlying

---
 include/etl/utility.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/etl/utility.h b/include/etl/utility.h
index 00ba8ca8..81c8c562 100644
--- a/include/etl/utility.h
+++ b/include/etl/utility.h
@@ -138,9 +138,9 @@ namespace etl
   // Gets the underlying type of an enum.
   //***********************************
   template <typename T>
-  ETL_CONSTEXPR underlying_type_t<T> to_underlying(T value) ETL_NOEXCEPT
+  ETL_CONSTEXPR typename underlying_type<T>::type to_underlying(T value) ETL_NOEXCEPT
   {
-    return static_cast<underlying_type_t<T>>(value);
+    return static_cast<typename underlying_type<T>::type>(value);
   }
 
   // We can't have std::swap and etl::swap templates coexisting in the unit tests