I tried to update my system with emerge --sync && emerge -uavtDnN world, when
confgiure attempts to determin target config.sub fails (missing arg), removing confcache from features and lzo build fine
Created attachment 105465 [details]
confcache has been removed from the tree -> NOTOURPROBLEM
Portage should warn/error about deprecated features silenty introducing breakage IS your problem
Portage already warned you that confcache ebuild doesn't exist any more.
Nothing to fix here.