If it's not hard, he is not constipated and does NOT need a suppository! It is totally normal for BF babies to go this long (or longer) between poos, after the first few weeks, of course. Breastmilk is so well-digested that there is little waste.
Are his poos super hard? THat's the sign that he is constipated. If they are more firm than before, that's only because of the solids. Adding solids might be why he's going so long, too.
For gas, do you "bicycle" his legs? That will go far in helping to relieve gas. You'll probably even hear some little toots when you do this!
Many people use gripe water and it is very safe. I've never used it, so I can't give testimony, but many people report how well it works. Others use baby gas drops (mylicon) which are supposed to be safe as well. Again, I haven't used them so I don't know how effective they are.
Oh, and that "gassy foods make breastfed babies gassy" business is not true, according to kellymom.com . things like milk, which are enzymes, can actually affect baby, but mom eating broccoli or beans is not really going to affect most babies. http://www.kellymom.com/babyconcerns/gassybaby.html
Now dairy is quite often a problem with BF babies. After all, they're not baby cows and were not meant to drink milk made for baby cows from the beginning. Dairy in mama's diet is often a big cause for problems. You can try eliminating all dairy, see if that's the case, then slowly add it back into your diet to see. http://www.kellymom.com/babyconcerns/food-sensitivity.html Again, though, the idea that other foods as triggers for gas is not well founded in research. but if YOU find something that triggers your baby, avoid it and see if it helps.
Good luck. I would really encourage you not to give your baby a suppository, nor try karo syrup like some people may tell you nor try to stick a thermometer in there to help stimulate things (I say these last two, because well-meaning people very often suggest it). You don't want to have to depend on those things to make him go. Once he starts eating apple sauce, things may change anyway. But don't feed him apple or prune juice just to make him go. Again, you don't want his body to have to depend on those things to go.