I recently had to build a file for multiple operating systems and had to figure out a way to enable a feature that is only available on Mac OS X 10.5 and greater, and Windows.
Here’s how I did it:
#if (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5) || defined (_WIN32)
#include
#endif
Now, technically there is no harm with including omp.h with your Mac project, I’d like using that as an example as opposed to using Cocoa.h/Afx.h.