Mac users who’ve been smug for years over how secure their OS is, could be in for a rude awakening if news out of the Black Hat Security Conference is true.As Macs have slowly gained market share on PCs — 9 percent of the market in the second quarter of 2009 and growing — the interest in hacking them has increased. The advances in security for the computers, however, has not kept pace, experts said at the Black Hat security conference in Vegas.Apparently, this time, what happens in Vegas is not staying there,