Ok, this is not gonna work like this. The sample code you show uses gobjects to start its own loop and do event handling all through it. gobjects is basically a glib task handling system. It's in fact its own execution system and is for instance used as base of gtk and in extension GNOME. But these are build on top of gobjects. LabVIEW has its own execution system and marrying two of them together is a major exercise in coding. In fact it is almost never done since it is so difficult to do right.
You will need to try to find the lower level interface of this aravis library. It will require you to call lots of functions with the arv_ prefix and similar, but you must avoid anything that starts with g_. Basically you would need to start writing something like IMAQdx with many of its functions but instead of calling into IMAQdx you call into the arvis library. It's doable but not for the faint of heart.
Basically trying to interface to image acquisition hardware and libraries is very difficult. Always! And there is a reason these libraries cost money and there are very few freebies here.
The Arvis library itself seems to be free. Its LGPL licensing can be problematic for anyone wanting to use it for a commercial program. And while it states to be LGPL there are actually files in there that state to be GPL. So licensing is not completely clear cut there. Incorporating GPL software in anything other than GPL software is basically impossible.