The pip package is for python 3.6, but installs pip for all versions of
python. Apparently. Including python 3.7.
So do all other packages, especially the ones where it doesn't work but
pip thinks it is installed anyway. Force a reinstall.
D lang compilers have an option -release (or similar) which turns off
asserts, contracts, and other runtime type checking. This patch wires
that up to the b_ndebug flag.
Fixes#7082