bug#43110: Namespace Rsvg not available (syncthing-gtk)

[Simen Endsjø]

I just installed guix using the binary installation script on 
Manjaro.
Installed syncthing-gtk, but I get an error when trying to run the 
application:

   Traceback (most recent call last):
   File 
   "/gnu/store/6h3hg1z7n8rpg4lw18hya48acrsmzkxq-syncthing-gtk-0.9.4.4/bin/.syncthing-gtk-real", 
   line 19, in <module>
       gi.require_version('Rsvg', '2.0')
   File 
   "/gnu/store/ns2dm6072h4crria79gid82ml37ab288-python2-pygobject-3.34.0/lib/python2.7/site-packages/gi/__init__.py", 
   line 129, in require_version
       raise ValueError('Namespace %s not available' % namespace)
   ValueError: Namespace Rsvg not available