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.
This issue covers various changes for the macOS installers provided via python.org for 3.7.0.
- Provide a provisional new installer variant for macOS 10.9 and later systems with 64-bit (x86_64) architecture only. Apple has made it known that future versions of macOS will only fully support 64-bit executables and some other third-party software suppliers have chosen 10.9 as their oldest supported system.
- Support **Tcl/Tk 8.6** with the 10.9 installer variant.
- Upgrade **OpenSSL** to 1.1.0g and **SQLite** to 3.22.0.
- The compiler name used for the interpreter build and for modules built with **Distutils / pip** is now _gcc_ rather than _gcc-4.2_. And extension module builds will no longer try to force use of an old SDK if present.
