What should i use if i want to glue climbing holds to a cement wall?

You should seriously consider other options. I doubt that the holds will stay on, and when they come off they will probably utterly destroy the surface. Plus you will never be able to rearrange them. It does not take much effort to construct a basic free-standing bouldering wall out of plywood. At the very least you should investigate drilling bolt holes instead, or floating a sheet of plywood in front of the wall to drill into. Though possible, I wouldn't recommend drilling directly into the concrete.... you'll need special bolts that you'll also have to somehow fit to the holds, and even then I have my doubts about how well they'd hold. If you are absolutely set on gluing them on... Gorilla Glue maybe?