Up git Street without a paddle

I recently updated OSX to El Capitain (10.11). Over all I think it’s a great update. Nothing stellar, but stabilises a lot of stuff from Mav.

It did stuff up my merge tool of choice in git though. I prefer diffmerge to the standard on OSX which is filemerge.

The fix took me a while to find, after trying a lot of suggestions on Stackoverflow.com.

Here it is just for you.