Information: USE="v4l2" has been removed from gentoo-x86
Versioned USE="v4l2" has been removed from Portage.
linux-headers-2.6.38 dropped support for video4linux 1.x and we have
linux-headers-2.6.39 stable now.
USE="v4l" is now used for video4linux 2.x and/or libv4l userspace libraries.
So anything using USE="v4l" for video4linux 1.x is a bug. There is no
such thing anymore.
For example, broken x11-misc/x11vnc here: