This question is based purely on publicly released documents regarding the introduction of application extensions in iOS.
With the introduction of app extensions in iOS
You can define your own macro.
In the project settings use the dropdown in the topbar to select your extension target:

Then:
- Click
Build Settings- Find (or search)
Preprocessor MacrosunderApple LLVM 6.0 - Preprocessing- Add
TARGET_IS_EXTENSIONor any other name of your choice in both the debug and release sections.
Then in your code:
#ifndef TARGET_IS_EXTENSION
// Do your calls to UIApplication
#endif