I would like to install the following change that introduces a
GStreamer-based media widget.

It depends on GStreamer, gst-plugins-base, and gst-plugins-good and is
thus a compile-time option.

Right now, it can only display a test pattern, but getting that to work
and perform decently was a challenge (for instance, offscreen rendering
is not an option, instead the pipeline is dynamically built based on
available xwidget views, utilizing hardware acceleration and video
decoding if available).

WDYT?