| Build and link with private copy of Tcl/Tk 8.6 for the macOS 10.6+ | |
| installer. The 10.9+ installer variant already does this. This means that | |
| the Python 3.7 provided by the python.org macOS installers no longer need or | |
| use any external versions of Tcl/Tk, either system-provided or user- | |
| installed, such as ActiveTcl. |