Here are ports for Tcl/Tk 8.6a2. I'm not suggesting they go into the tree - they're for anyone who wants to try out 8.6 and should eventually become the 8.6 ports when 8.6 is released.
There's a directory conflict that prevents 8.5 and 8.6 from being installed simultaneously. This is new and I'm not sure what to do about it yet.
tcl-8.6a2-port44.tar.gz
Description: application/gzip
tk-8.6a2-port44.tar.gz
Description: application/gzip