How can i define my own BUILD mode?

Hi there,

I would like to know how can i create custom build configurations. For example, we can include specific codes in Shipping build if we wrap them like this:

#if UE_BUILD_SHIPPING
    //do stuff
#endif

Just like that, i want some features in my game to only appear on demo build. So i would like to do something like this:

#if GAME_BUILD_DEMO
    //do stuff
#endif

quick bump