In different languages I see the name written in different ways. But in fact in the same language you also see the name written in different ways. Sometimes I read GADHAFI, other times GADDAFI. But there are other ways too!
You also can read MUAMMAR AL-GADDAFI. I think that Gaddafi refers to his tribe. As you may know Lybia is a country of tribes.
GADHAFI yields 5,590,000 results in google.com.
GADDAFI yields 67,500,000 results.
Let me see in the media ..:
VOICE OF AMERICA: Gadhafi
NYT: Muammar el-Qaddafi
The Guardian: Gaddafi