Due to cleanup in games-action/bzflag-2.0.12.ebuild (see URL) it's not possible to install bzflag and curl with IPv6 at the same time: # emerge -uDvNa world These are the packages that would be merged, in order: Calculating dependencies... done! emerge: there are no ebuilds built with USE flags to satisfy ">=net-misc/curl-7.15.0[ares]". !!! One of the following packages is required to complete your request: - net-misc/curl-7.18.2 (Change USE: +ares) (dependency required by "games-action/bzflag-2.0.12" [installed]) (dependency required by "world" [argument]) This is caused by net-misc/curl-7.18.2 which switches of ares support if ipv6 is required (c-ares does not support IPv6 yet). Original bzflag ebuild had weaker dependency on curl with ares (see bug #200798) and worked very well linked against USE="-ares ipv6" curl. I suggest to revert this change in bzflag-2.0.12.
I thought it was in response to a bug but it doesn't appear to be needed. I removed the use dep.
Thanks. One hint: Remove now meaningless EAPI=2 statement from the ebuild to comply with Gentoo QA.