Does your gym have dip bars? when I was in a gym with just a smith machine I used to use the dip bars to load the bar... to be honest neither option is exactly ideal as such, but squats are fundamental, so use the smith if you don't have any other choice and supplement it with the stuff like ExtraMile suggested.
Using the dip bars is a great idea, lol if I did it at my gym Id probably knock some sucker out with the bar cuz the dip bars are right near the door into the gym lol