webkit-gtk has open security bugs and won't build/run on ppc or alpha. arm TBD. We need to drop keywords on both those arches. This bug is to remind me to drop keywords and do the QA work.
I suggest you open a PR in Github where CI service will spot most of the errors coming from reverse dependencies.
What problems are there for alpha? Why is the maintainer not assigned or CCed here?
slyfox did this in: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=aedfd315d64fc1a6418ca8135151fefb6032c092 https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=927bcd18aa392ed56288517e8eb2499bd6b4d803