In my opinion, and those of most others, it's not worth trying to jerry rig your headset to your computer.
For the time and money you're going to put into finding and buying an adapter, you'll be much better off buying something purpose built for your computer. If you do find an adapter (I haven't found one for my U-94 connector in my 5 minutes of curiosity), everything will still sound terrible.
There's literally a $12 headset on Amazon that will sound better than real Comtacs, much less Z-tac knock offs.

Unless your an audiophile, just drop $40 on a headset to get decent sound, and especially, a decent mic. You won't get to hear the benefits of how your mic sounds, but you'll find that you'll quickly lose friends that want to talk to you, if you buy a dollar store mic.