yan12125
Fix build-time ensurepip
It's broken by a CPython bug, which attempts to install pip on the host even for cross-builds.
Current workaround: run ensurepip on the phone. Enter an adb shell and run:
$ python3.7m -m ensurepip
$ python3.7m -m pip install --upgrade pip setuptools # This is optional
Also, latest pip hang after running most commands. Android doesn't allow non-root processes to create hard links, which breaks the lockfile module. See https://github.com/pypa/pip/issues/3532.
Update: pip is moving away from pylockfile: https://github.com/pypa/pip/issues/4766
Also related to https://github.com/pypa/pip/issues/3063. Possible fixes at https://github.com/yan12125/pip/tree/pip-3063 and https://github.com/yan12125/setuptools/tree/pip-3063