TARGET_OS_IOS evalutes to 0 when using iOS scheme

In a cross-platform project (iOS/macOS) some files are shared between platforms i.e. they have the "Target Membership" checkbox set for both the iOS and the OS X target. But

TARGET_OS_IOS
evaluates to 0 in both the iOS and the OS X scheme. Consequently,
TARGET_OS_OSX
evaluates to 1 in both schemes. A cmd-click on the macro opens TargetConditionals.h in the OS X SDK for both schemes.


Only when I remove the OS X checkbox under "Target Membership", both macros evaluate correctly in both schemes.

When I copy the complete project folder over to another user on the same machine, some of the files suddenly work correctly, but not all of them !?!?!

Does anybody know what's going on? I made a clean Xcode re-install just before I started this new project.

TARGET_OS_IOS evalutes to 0 when using iOS scheme
 
 
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