billypilgrim [1] filed a deletion request for eigen32 [2]: It seems unlikely that anyone is using this outdated version of eigen (apart from anything you have to build qt4 for it) and having a package in the AUR which "provides" eigen3 is causing problems.
[1] https://aur.archlinux.org/account/billypilgrim/ [2] https://aur.archlinux.org/pkgbase/eigen32/
