I think the vmware-workstation ebuild should be split in vmware-workstation-3 and vmware-workstation-4 as you can have a valid (non-testing) license of version 3 which is replaced by version 4 (for which you don't have a valid license) every time you update the system by doing an emerge sync and emerge -u world.
Don't SLOTs do this? Apparently, it is not enough, because VMware 3 AND 4 are installed into the same directory. This is an INVALID bug because you are not supposed to do blind world updates. See the forum threads about how to mask Apache2. GTK+ is not split into 1 and 2, why should you worry?
*** This bug has been marked as a duplicate of 4698 ***