Function all_flags_equal

tests/BS_thread_pool_test.cpp:501–508

 */
template <typename T, typename V>
bool all_flags_equal(const T& flags, const V& value)
{
    return std::all_of(flags.begin(), flags.end(),
        [&value](const auto& flag)
        {
            return flag == value;
        });
}

/**
 * @brief Check if all of the flags in a container are set.