darwinbuild-1605

This release includes one bug-fix from the previous release:

• When invoking xcodebuild, the code-signing identity is overridden to - (sign for this machine only). This feature was removed in darwinbuild-1600, but I have since found that Xcode cannot always find the signing certificates in the keychain when run by darwinbuild.

Please also see the release notes for darwibuild-1600, as that release (and, by extension, this one) is not fully backwards-compatible with prior versions of darwinbuild.