The Xcode 7 Release Notes have a section headed "Notes" that mentions "bitcode" 15 times without suggesting or stating in any way that bitcode is not supported for Mac OS X apps. These notes state, without any qualification, that developers "need to include bitcode for Xcode 7 development" and similar phrases.
When I looked at the What's New in Xcode document released a week ago, I saw that it has a section headed "App Thinning" that begins, "With Xcode 7, you are developing apps for three diverse platforms that run on a variety of devices and configurations," without naming the three platforms. Since this statement appears in the section headed "Xcode 7.0," and it is only the "Xcode 7.1" section that says Xcode now supports development for Apple TV, I concluded that the reference to "three diverse platforms" means OS X, iOS and watchOS, but the document makes no effort to specify them. It does at the end say, "See App Thinning (iOS, watchOS)." The fact that it refers to two of the three supported platforms offers no clue that OS X is not the third supported platform. When I close and reopen the document, a different version of comes up and the wording changes to simply "See App Thinning," which offers even less of a clue.
So, Chris, I'm very surprised at your assertion. Like many OS X developers, I don't have time to watch all of the WWDC videos. But I do spend substantial time every day reading the Apple tech news, and I like to think I'm keeping up to date. I especially rely on key documents like the Release Notes to tell me things I need to know. If bitcode does not apply to OS X, how on earth did anybody let the Release Notes go public without mentioning that rather important fact? Especially since the Xcode 7 Release Notes expressly tell developers who rely on third-party frameworks to contact their providers and get a bitcode-compliant framework version for applications developed on Xcode 7.
I'm verging on a rant here, so I'll end it now by asking you (and everybody) if you can point me to something with some official standing that makes clear bitcode does not apply to OS X.