You could include the ofxOMXPlayer only if you are on the raspberry pi
Keep in mind that ofxOMXPlayer is not 100% drop in replacement for the ofVideoPlayer so you'll have to put a lot of #ifdef all over your code...
If you want to keep compatibility on both platform I suggest using ofVideoPlayer instead of ofxOMXPlayer.
There is a trick to activate hardware acceleration described here :
play-video-controlling-speed-and-direction raspberry pi