Fix build on arch linux

Fixes the following issues:

* OpenNI/OpenNI2 https://github.com/OpenNI/OpenNI2/issues/45
* OpenNI/OpenNI2 https://github.com/OpenNI/OpenNI2/issues/46
* OpenNI/OpenNI2 https://github.com/OpenNI/OpenNI2/issues/47
* OpenNI/OpenNI2 https://github.com/OpenNI/OpenNI2/issues/48
* OpenNI/OpenNI2 https://github.com/OpenNI/OpenNI2/issues/49

These fixes are necessary to build on platform

* g++ (GCC) 4.8.1 20130725 (prerelease) 
* Linux 3.11.4-1-ARCH x86_64 GNU/Linux

However, the fixes are of quite general scope.

See also: http://www.python.org/dev/peps/pep-0394