adds support for click extensions on osx arm

[cdhanna]

Hey, I noticed that the lovely click extension methods weren't working on my ARM based mac laptop. It was throwing an error about trying to load the wrong architecture file, and I noticed that there was no branching logic for the ARM vs not-ARM in the click extensions.

I tried to follow some convention, and I did a little ternary switch in the extension method to send ARM based OSX stuff to a new namespace, that is an exact copy of the old OSX click stuff; except it uses the already existing osx_arm.so file.