rayh/xcoder — pull request #81 by ArloL (2013-11-03 15:35:04+00:00)
Title: Initialize sdk with nil, use only when overriding the sdk to use

It is unnecessary to initialize the project sdk value with 'iphoneos'. xcodebuild does this automatically for the targets. You only want to be able to set the SDK value to override the settings.

Initializing the sdk with nil achieves this.