It has been a longtime policy that you don't stop builds because of mismatching kernel options. Not only this is currently hitting me on one of my servers, but it makes tinderboxing impossible.
I see no option as fatal in ebuild: CONFIG_CHECK="~CHECKPOINT_RESTORE ~NAMESPACES ~PID_NS ~FHANDLE ~EVENTFD ~EPOLL ~INOTIFY_USER ~IA32_EMULATION ~UNIX_DIAG ~INET_DIAG ~INET_UDP_DIAG ~PACKET_DIAG ~NETLINK_DIAG" What concrete error are you getting?