The net-libs/webkit-gtk ebuild SRC_URIs point at nonexistent *.tar.xz files.

• Related Gentoo bug: https://bugs.gentoo.org/show_bug.cgi?id=524584#c18. Looks like the original tarballs were removed because they contained non-free images.
• Related (Funtoo) forum post: http://forums.funtoo.org/index.php?/topic/210-failed-to-emerge-net-libswebkit-gtk-244-r200-error-404-not-found/

Ebuild patch: https://bpaste.net/show/43f08c8ff760