When enabling the "mark-played-items" configuration option, there
is a repeatable segfault of the application as soon as you
attempt to watch a video file.

I have attached a backtrace

It turns out this is a lack of a default in
mark-played-items/mark/content, despite this being documented as
optional

A quick workaround is to add

<mark-played-items enabled="yes" suppress-cds-updates="yes">
  <string mode="prepend">*</string>
  <mark>
   <content>video</content>
  </mark>
</mark-played-items>

to the config file.  I believe the following patch should add the
default values if none are set.