Getdents system call was superseded with with getdents64 in Linux 2.4 (January 2001). New architectures, such as 64-Bit ARM opt out not to support legacy system calls, and getdents is one of them. 

Since getdents64 has been supported for over a decade, I don't think adding ifdef to support both makes sense. Using getdents64 cleans up the current _posixsubprocess code as the entries are long long everywhere.

The attached patch makes _posixsubprocess module compile on 64-Bit ARM and causes on regressions on the python3.3 testsuite on x86 and x86_64

Gregory, do you have time to take care of this?

New changeset 30e643e36bae by Gregory P. Smith in branch '3.3':
Issue #16962: Use getdents64 instead of the obsolete getdents syscall in
http://hg.python.org/cpython/rev/30e643e36bae

New changeset 7ab1c55fcf82 by Gregory P. Smith in branch 'default':
Fixes Issue #16962: Use getdents64 instead of the obsolete getdents syscall
http://hg.python.org/cpython/rev/7ab1c55fcf82

looks sane and cleaner than the silly x32 hack in there, i'll take care of it.  FYI - your patch forgot to add the "unsigned char d_type;" struct member before name.  fixed and applied.

When i wrote that code I was probably assuming that sticking with the ancient syscall made more sense for compatibility.  I'm happy to see that compatibility goes the other way on this one.