android-ndk-r14 introduces "Unified Headers" [1] and is planned to be released late january/early february 2017 [2].

__ANDROID_API__ is not anymore defined in 'android/api-level.h' that is currently included by Include/pyport.h, and is passed instead with -D__ANDROID_API__=$API when compiling. And 'android/api-level.h' is now used to set the API level to 10000 as a Magic version number for a current development build when __ANDROID_API__ is not defined (see attached file).

Adoption of android-ndk-r14 should be made with the following changes:
* Remove the include of <android/api-level.h> in Include/pyport.h.
* Update configure.ac to abort when __ANDROID__ is defined and __ANDROID_API__ is not defined.
* Revert the changes made in issues #28538 and #28762, android-ndk-r14 fixes the problems raised in these two issues.

[1] https://android.googlesource.com/platform/ndk.git/+/master/docs/UnifiedHeaders.md
[2] https://github.com/android-ndk/ndk/wiki

Thanks for compiling up necessary changes for NDK r14! Seems that indicates future Python versions will require at least NDK r14 to build?

Another headache from unified headers is that it requires different --sysroot in compilation and linking. Currently setup.py/distutils does not cope with it well. See my dirty hack at [1] for an ad-hoc workaround.

[1] https://github.com/yan12125/python3-android/blob/master/mk/python/distutils-android-sysroot.patch

> Seems that indicates future Python versions will require at least NDK r14 to build?

Yes.

New changeset c06c22e9a9fb9326e79fcf1551601eacc1fd457d by xdegaye in branch 'master':
bpo-29040: Support building Android with Unified Headers (GH-4492)
https://github.com/python/cpython/commit/c06c22e9a9fb9326e79fcf1551601eacc1fd457d