Building multiple ports (using macports) at the same time

I'm trying to build gcc45 +gfortran on my macbook pro core duo 2 and obviously it is taking a while (A few hours I'm told). I'm wondering if its possible (safe) if I build some 开发者_C百科other ports / packages in another terminal in the mean time?

Building multiple ports in parallel is blocked by a lock-file.

You could override that but it is not safe to do so.