Revert the changeset commited at issue #20307 as the compilation does not fail anymore on android API level 21.

Patch attached.

@shiz: Can we settle on API level 21 or is there any reason to leave this in?

I have no problem just removing the #ifdef as Android API 21 is now old enough (Lollipop / 5.0) that anyone building Python 3.6 for use on Android is probably fine with it.

If there is a #define that can be used to test the android api level at compile time, adding that to the #if is another approach and would keep people who are trying to run something on an older version happy.

New patch taking into account Gregory's comments.
API level 19 is the last to have a sys/linux-syscalls.h header.
All levels have a android/api-level.h header that define __ANDROID_API__.
There is no API level 20, and SYS_getdents64 is defined at API level 21.

The patch is simpler since android/api-level.h is now included in pyport.h by changeset 09af54099973.

posixmodule_3.patch looks good to me. Gregory has already approved the approach, so I think you can go ahead and commit this.

Stefan Krah: "posixmodule_3.patch looks good to me. Gregory has already approved the approach, so I think you can go ahead and commit this"

I concur with Stefan: LGTM.

New changeset 4ef3a93e1be2 by Xavier de Gaye in branch 'default':
Issue #26862: SYS_getdents64 does not need to be defined on android API 21.
https://hg.python.org/cpython/rev/4ef3a93e1be2

Any plans to fix this in 3.5 as well?

cschramm: AFAIK only Python 3.6+ has experimental Android support. 3.5 or below are not supported.

Sorry, AFAIK there is no plan to retrofit the Android changes to 3.5.
Note that Python 3.6 is expected to be released in few weeks, by next mid-december.

Well, the 3.5 code checks __ANDROID__ as well and works pretty fine on Android, but if it's not supposed to be supported, we'll have to upgrade to 3.6 then.

Thanks for your work! :)