Plz help need advice with crying lost/stray cat!!!?

I have been seeing this lost/stray cat now for about a week. I feed the feral cats outback so i figured he was just stopping by at night to eat. Well... That's not the case now! He has been crying now at my door for at least three hours off and on. If he's not there he is asleep on our shed. He is extremely affectionate with people and other animals too and wants to be petted nonstop. He even nudges your arm if you stop petting him. But I feel Soo bad! All he is doing is crying. He is under weight and only looks to be no older than a year. So what can I do to stop him from crying? I tried bringing him in but my cat was not having it. And he started to spray in here also so I just put him back out. So what advice can you give me about trying to find him a forever home? Because i've asked around and even posted him up on the computer but no one seems to know who he belongs to! I am in Pennsylvania if that helps... Thanks in advance!