lang/python3*: Fix cross-build by patching out broken readline crud.

Python's setup.py tries to decide whether readline is available by
running readelf on the path it thinks it can find to libreadline.so.
Since we always use a single static readline/curses choice in Pythin
(readline, not editline, with (fake-)ncurses), just patch all that
buggy detection goo away.

No new maintenance burden because this logic has been ripped out of
Python 3.12 anyway.  Python 3.8 skipped for now because it doesn't
cross-build at the moment anyway -- more work needed to make that
happen (and it's not as easy as Python>=3.9 as I recall).

(riastradh)