The upstream has renamed backupmail to pimsettingexporter. See http://commits.kde.org/kdepim/b94cec27cd4b1f88721f9115da9efa41322c1ea7 . Reproducible: Always
Thanks, this has since been fixed. http://git.overlays.gentoo.org/gitweb/?p=proj/kde.git;a=commitdiff;h=19d0314ef7b827f61b836e232a145cf750774807