External links have an missing icon in front of them for offline docs

When trying to build the offline docs I noticed that all external links have lots of whitespace in front of them. The reason is that the offline.css stylesheet actually tries to put an image in front of all links that starts with either , "http://", "ftp://" or "https://" to indicate that a link will actually jump out of their "local" documentation.

The style sheet has this css:

a[href*="http://"], a[href*="ftp://"],a[href*="https://"]
{
text-decoration: none;
background-image:url(../images/ico_out.png);
...

However, there is no ico_out.png in that location.
The problem seems to be that the ico_out.png should come from the template, but it is not copied for some reason unknown to me.

This could be related to https://bugreports.qt-project.org/browse/QTBUG-13651