Considering the tests don't work anyway nowadays, I'd say kill it with RESTRICT=test. Though it would be useful to check if glibc breaks tests only, or if the package is broken itself. Please keep this bug open as long as there's RESTRICT=userpriv in the ebuild.
[master 63c2feb] media-gfx/gtkimageview: tests are severely broken and not meant to be run (#483952), stop relying on userpriv (#516580), update eapi, don't rebuild gtk-doc. 1 file changed, 14 insertions(+), 37 deletions(-)
