gcr: Fix gcr-viewer build errors
gcr: Fix gcr-viewer build errors

https://bugzilla.gnome.org/show_bug.cgi?id=658319

stefwalter/gcr,Distrotech/gcr,stefwalter/gcr,Distrotech/gcr,stefwalter/gcr,Distrotech/gcr,Distrotech/gcr,stefwalter/gcr