Since /usr/bin/scanelf is provided by app-misc/pax-utils, the pax-utils.eclass should depend on it. Packages relying on this eclass can be broken or not work properly because of this since their pax-mark will fail if app-misc/pax-utils has not been installed by hand by users. Thanks
My bad, portage & al were not up to date and caused the missing dep. pax-utils is indeed a dep of portage since then. Thanks