I succeeded with building my app for iOS and my first step in publishing the app in App Store was opening generated .xcodeproj file in XCode, but XCode froze displaying rotating progress indicator and wait cursor.
I was able to compile and debug my app on MacOS with QT Creator:
All C++ code compiled successfully, but something went wrong with OpenGLES shaders. It is probably because I included OpenGLES headers from a wrong place.