For any still interested in this…
I’ve gotten the same errors using a brewed copy of tcl-tk after modifying the r.rb formula args section as indicated in your post. The solution, in my case, was to point the
--with-tk-config arguments to the system tcltk frameworks:
While those formula edits are pretty straight-forward and have worked for me in the past, after a recent Mac OS update I found I could no longer brew
r with tcltk support. Upon inspection the tcltk config files were no longer present where they were expected. It turned out that the update removed my Command Line Tools and, unbeknownst to me (perhaps obvious to other who know more about this stuff than I do), the
tkConfig.sh files are only present when CLT is installed. After reinstalling CLT the formula installed as usual with tcl-tk support.