I have attempted to archive my project for submission to App Store, however, every time I get errors "use of undeclared identifier" for everything related to google iOS SDK. The application itself runs and builds flawlessly with the discussed SDK integrated, the only thing that fails is the archive process. I have tried both cocoa pods and manual method of integration (separately, of course). Furthermore, I used the latest xCode versions (6.4 and 7 beta 4) on two different macs running OS X 10.10.4. This is the guide I have been using.
Your issue has something to do with the configuration of archiving in combination with your Release settings. If you change the scheme settings
Command + < to use the Debug configuration for archiving, you may be able to successfully archive your app. This means that somewhere you are probably not matching the Debug and Release configurations.
See the following screenshot for example project Build Settings that are missing the Swift bridging header in release:
bridge.h to the release configuration and you will be able to build with the Release schema and you will be able to archive under release configuration.