In my app code I used TARGET_OS_IPHONE/TARGET_OS_IOS for SDK 15 and 16.
After go on SDK 17.x these macros are not defined.
In my investigation, I found that in /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/include/TargetConditionals.h
__is_target_environment(macabi) return false hence the issue.
Could you please verify and explain, if I do not understand / use correctly.
Regards, Alexei