Can't build on Mac after https://reviews.llvm.org/D113650

Some recent python changes have stopped by cmake configure from working on fresh checkout on macOS. Details in the comments of the diff in ⚙ D113650 [lldb] fix -print-script-interpreter-info on windows as to how I am configuring cmake. If anyone has any example of how to properly set the python stuff to work around the issue, it would be most appreciated. Else I would like to revert this diff and all associated fixes that came in afterwards so that I can get some work done.