[kazinator]

The #ifndef trick is highly portable and has clear semantics that is under the program's control. Nobody needs a platform-specific, underspecified alternative that saves two lines of code compared to the robust, portable solution. If I am paying with nonportability, I want "bang for the buck": like faster or smaller code on the target, or detailed control of its hardware or host platform features. I don't need unspecified build machine behavior so much. I am not programming the build machine.