I've got a user who likes ksh, and I besides being amazed with the time it takes to emerge ksh, I discovered that pdksh was perfectly happy to emerge right over the /bin/ksh that ksh had created. Reproducible: Didn't try Steps to Reproduce: 1. emerge ksh 2. emerge pdksh 3. Actual Results: the /bin/ksh that the ksh package created was overwitten by the /bin/ksh that pdksh created. Expected Results: emerge should have complained that the two are mutually exclusive, or put them in different places, or even just made some noise...
I maintain ksh, and block pdksh from there. it looks like pdksh is orphaned (no maintainer), so I'll add the block there.