ok... I was very surprised because this is the first time I see such error...
I'm trying to create a new package for [pulseeffects](https://github.com/wwmm/pulseeffects) and it needs to link to gstreamer to work.
In fact `pulseeffects` needs `GstInsertBin` to get built (see [comment](https://github.com/wwmm/pulseeffects/issues/22#issuecomment-347897269)) , so I must modify the template to add `gobject-introspection`.
I hope it's ok ?