No. There is no universally understood, crystal clear signal.
It's 2012. You could just ask. Hesitantly if you like, but in any case politely, making it clear you don't want to cause any offence. Maybe you saying it first ( about you ).
Or you could try talking about things like pop music, art, how you admire certain athletes, cooking, literature, clothes, nightclubs ...
But even then, you'd still have to confirm directly at some point.
And liking all the "gay" culture aspects isn't actually the point anyway. I've mentioned that before ...
Anyway. I think you exaggerate the risk, and if there is any, just remember that all the worthwhile things in life come with some risk. It can usually be controlled and managed, but not eliminated.
Good luck. Just know that there are many, many people out there who feel the same way you do, and not just over the sexuality issue itself, but about other people's despicable prejudices, and the loneliness that can sometimes cause. For a while. Loneliness based on difference.
But in a year or two, your life will turn around.
I don't know if you know how a LASER works ? At a certain point, the atoms in the lasing substance all start to beat to the same pulse, as it were. Quantum coherence. They respond to each others energy in a kind of chain reaction.
You and the people around you will find a way to do that. Discussion and conversation passes the energy around.
Shine.
:smile: