Fixes to compile with dmd 2.066

With the latest dmd 2.066 it was not compiling without this modifications.
I did saw that pull request after I did mine, I didn't checked to see if the library needed opCmp for other purposes so I left it there, that pull request has an assert to check if the size of the struct has changed before return the actual hash, I think that's a good idea because on mine I only did a visual check and saw that the struct size was equivalent to a ulong and hardcoeded it.