For Android I've been focusing on submitting patches to CPython 3.4/3.5 for things that can be
argued to be "just cross-compilation bugs" in the Cpython source.
For example:
http://bugs.python.org/issue21668 just fixes a missing -lm flag during compilation (that doesn't
matter on Linux/MacOS/Windows, but is technically required, and causes problems with the
Android dynamic loader if it is missing).
http://bugs.python.org/issue20306 just takes care of the fact that pw_gecos isn't actually required
by Posix.