If it is just wolf whistling, I used to not have a problem with it. One guy once also offered me a job as a hod carrier...in jest, of course. I thought it was funny. I used to get catcalls and horn blowing from passing lorry drivers, too. I don't see the problem and think anyone who lets that be a problem is overreacting. I wish I could still draw those reactions, lol. We are becoming hypersensitive and I am minded of the old saying, sticks and stones may hurt my bones etc.
If someone's way is impeded and it becomes more than a distant whistle/comment, but rather a close encounter, then that is harassment. All IMHO.