How to build boost python with python3

[indigodomo]

Seems like it should be possible to build boost python with a python3 install from python.org, installed in:

/Library/Frameworks/Python.framework/Versions/3.9

I've tweaked the boost.sh script with:

./bootstrap.sh --with-libraries="$BOOST_LIBS_COMMA" --with-python=python3 --with-python-root=/Library/Frameworks/Python.framework/Versions/3.9/ --with-python-version=3.9

and it still insists on building:

src/boost_1_75_0/macos-build/stage/lib/libboost_python27.a

Given that Apple is going to remove Python in the next version of macOS, it would seem like the need to update the script to build from python.org's default install directory (or at least pass through the appropriate params).

Anyone else tried this and succeeded?