The Best Glide Distance is achieved with a speed that depends on the wind. With the optimum glide speed adjusted for wind you will be able to reach more places, not less.
I am not arguing that.
I am arguing that the best glide speed does not change as a result of different winds.
The best glide distance, I have already stated, is affected by wind, and therefore you can get different results, some times, but not always, better, by changing your speed.
But it is dangerous to think that you should adjust your glide speed for a headwind. To think that you can "dive for the landing spot", will lead to trying that when there is no headwind.
The safest thing to do is establish the best glide speed (which will not necessarily give you the best glide distance, but will give you the best lift to drag ratio glide, and thus the longest - timewise - glide), and then focus on a place within the 45 degree cone, then try to restart the engine, never losing track of your chosen landing spot, but also, not changing the speed because you think you might make it if you go faster - that leads to fatal crashes.