twig set block

use set instead of macro

{# If creating a responsive theme, you sometimes need to duplicate content in a template and a macro can be an option but sometimes the overhead is to much #}

{% set loginblock %}
    <li><a href="{{ url('login') }}">Log in</a></li>
    <li><a href="{{ url('signup') }}">Sign up</a></li> 
{% endset %}

... more html...

<ul class="nav nav-secondary">
        {{ loginblock }}
</ul>

... even more html...

  <ul class="nav nav-secondary nav-mobile">
        {{ loginblock }}
</ul>