Fails to build with Python 3.14

[opoplawski]

Fedora is starting to test building with Python 3.14.0a2. makefun fails to build with:

FAILED tests/test_generators_coroutines.py::test_native_coroutine -
RuntimeError: There is no current event loop in thread 'MainThread'.
FAILED tests/test_generators_coroutines.py::test_issue_96 - RuntimeError: There
is no current event loop in thread 'MainThread'.
FAILED tests/test_issues.py::test_issue_77_async_generator_wraps -
RuntimeError: There is no current event loop in thread 'MainThread'.
FAILED tests/test_issues.py::test_issue_77_async_generator_partial -
RuntimeError: There is no current event loop in thread 'MainThread'.

According to https://docs.python.org/dev/whatsnew/3.14.html#id3

Removed implicit creation of event loop by asyncio.get_event_loop(). It now
raises a RuntimeError if there is no current event loop. (Contributed by Kumar
Aditya in gh-126353.)