On Linux vserver systems, e2fsprogs is not required at all. Please make e2fsprogs support in libarchive optional as well, so that libarchive does not bring in e2fsprogs. It does build perfectly fine without e2fsprogs on Linux, and on BSD e2fsprogs isn't available anyway. Also watch out for the present automagic detection of e2fsprogs.
should be set in ebuild for 3.0.2