update macros for codecvt and support C++26 support on clang19

include/CLI/TypeTools.hpp

@@ -295,8 +295,9 @@ template <typename T>
 struct is_wrapper<T, conditional_t<false, void_t<typename T::value_type>, void>> : public std::true_type {};
 
 // Check for tuple like types, as in classes with a tuple_size type trait
+// Even though in C++26 std::complex gains a std::tuple interface, for our purposes we treat is as NOT a tuple
 template <typename S> class is_tuple_like {
-    template <typename SS>
+    template <typename SS, enable_if_t<!is_complex<SS>::value, detail::enabler> = detail::dummy>
     // static auto test(int)
     //     -> decltype(std::conditional<(std::tuple_size<SS>::value > 0), std::true_type, std::false_type>::type());
     static auto test(int) -> decltype(std::tuple_size<typename std::decay<SS>::type>::value, std::true_type{});

tests/HelpersTest.cpp

@@ -1520,6 +1520,7 @@ static_assert(CLI::detail::is_tuple_like<std::array<int, 10>>::value, "std::arra
 static_assert(!CLI::detail::is_tuple_like<std::string>::value, "std::string should not be like a tuple");
 static_assert(!CLI::detail::is_tuple_like<double>::value, "double should not be like a tuple");
 static_assert(CLI::detail::is_tuple_like<std::tuple<double, int, double>>::value, "tuple should look like a tuple");
+static_assert(!CLI::detail::is_tuple_like<std::complex<double>>::value, "std::complex should not be like a tuple");
 
 TEST_CASE("Types: LexicalConversionTuple2", "[helpers]") {
     CLI::results_t input = {"9.12", "19"};