meta: suppress warnings due to unused variables

src/entt/meta/meta.hpp

@@ -1573,7 +1573,7 @@ bool meta_any::set(const id_type id, Type &&value) {
 }
 
 [[nodiscard]] inline meta_any meta_any::allow_cast(const meta_type &type) const {
-    return internal::try_convert(internal::meta_context::from(*ctx), node, type.info(), type.is_arithmetic() || type.is_enum(), data(), [this, &type](const void *instance, auto &&...args) {
+    return internal::try_convert(internal::meta_context::from(*ctx), node, type.info(), type.is_arithmetic() || type.is_enum(), data(), [this, &type]([[maybe_unused]] const void *instance, auto &&...args) {
         if constexpr((std::is_same_v<std::remove_const_t<std::remove_reference_t<decltype(args)>>, internal::meta_type_node> || ...)) {
             return (args.from_void(*ctx, nullptr, instance), ...);
         } else if constexpr((std::is_same_v<std::remove_const_t<std::remove_reference_t<decltype(args)>>, internal::meta_conv_node> || ...)) {