Starting with net-fs/samba-3.4.6 (currently PMASKED), the samba ebuilds are not split anymore. Thus, there is no package samba-libs or samba-client anymore. Before unmasking this, please change the dependencies of kdebase-kioslaves[samba] such that for samba>=3.4.6 it requires samba, not samba-libs or samba-client.
@Patrick: This is directly for evil compile person, so earn your credits. Afterall you are maintainer of samba
Yes, yes :)