Just note about using this patch.

In my installation static content (images, etc.) for roundup-tracker
templates delivered via Apache via:

In httpd.conf:

<VirtualHost ...>
Define CSURL /static
...
 <Location /tracker/>
    ProxyPass ...

    #Pass variable
    RequestHeader set CSURL ${CSURL}
 </Location>
</VirtualHost>

In jinja2 template:

{# static content url#}
{%- set csurl = request.env['HTTP_CSURL']  -%}
...
 <link rel="stylesheet" type="text/css" href="{{csurl}/bootstrap.min.css">
...