In the ebuild:
# tests do not work with userpriv
Patch to restrict only when using tests attached.
Created attachment 331890 [details]
Assuming maintainer timeout.
+ 07 Jul 2014; Michał Górny <email@example.com> gtkimageview-1.6.4.ebuild:
+ Force RESTRICT=userpriv only with USE=test, bug #446628. Update HOMEPAGE. Set
+ SRC_URI to our mirrors since the original host is dead and the new homepage
+ does not carry distfiles.