[calcapt]

Think about this. The guy who issues you the clearance to taxi out to the runway is ground control and the guy that controls the runway is the tower controller. The ground controller is simply telling you to taxi out to the runway via whatever route he clears you for. Or, if he doesn't specify, go the way you want. It is implied that before you get to the runway ground will switch you to tower and he will tell you what he wants you to do with respect to the runway. Some small airports have the same guy filling both roles, but that is not the norm. It goes without saying that if you don't get switched to tower or ground gets occupied, you always hold short of the departing runway.

If he said "taxi to rwy xxx and hold short", he is saying things that don't need to be said and can be misinterpreted. For example, if I hear that specific clearance, I am wondering to myself "he wants me to taxi to the runway but wants me to hold short of what?" If he says "taxi to the runway" I know I am cleared to taxi all the way there, and won't plan on stopping before I get there. If he does want you to hold short of something before you get there, he will say something like "Rwy xxx, taxi Bravo, Delta, Uniform, hold short Victor. He mentions the runway in the clearance just so you know which one he plans on you using.