With -gstreamer, compilation will fail (since gstreamer doesn't exist), unless --disable-web-audio is also given (to econf). Apparently it's enabled by default. Reproducible: Always
Have you tested any other versions?
Nope :s. It's a huge hassle to compile this package. (Is there a good reason why this takes many hours to compile, even though the source is under 10mb, and other packages which are far larger take far less?)
Could you provide build.log and emerge -info?
I can confirm this with net-libs/webkit-gtk-2.2.4-r200
+ 11 Feb 2014; Pacho Ramos <pacho@gentoo.org> webkit-gtk-2.2.4-r200.ebuild, + webkit-gtk-2.2.4.ebuild: + web-audio relies on gstreamer (#500406 by Dennis New) +
*** Bug 501052 has been marked as a duplicate of this bug. ***