Function make_error_id

include/boost/leaf/error.hpp:796–800

namespace detail
{
    BOOST_LEAF_CONSTEXPR inline error_id make_error_id( int err_id ) noexcept
    {
        BOOST_LEAF_ASSERT(err_id == 0 || (err_id&3) == 1);
        return error_id((err_id&~3)|1);
    }
}

BOOST_LEAF_ATTRIBUTE_NODISCARD inline error_id new_error()