Portmaster error "The devel/llvm36 port has been deleted

I updated to the devel/llvm40 port. I had been using the deprecated llvm36. I did a portsnap update (which I do weekly) and ran portmaster -a. It kept aborting when it finished its scan with this message:
"The devel/llvm36 port has been deleted: Obsolete and unmaintained upstream
=====>>> Aborting Update
I've tried everything I can think of including recompiling portmaster.

Is there a solution for this?

Irrelevant. It's installed, so the package database knows it. And it's the installed package that needs to be removed.