Fix allocating memory in zone under 64 bit

[korbykob]

Fixes #27 by using the size of a pointer to align anything allocated by the zone.

[Mellurboo]

please actually push this its a right ballache

[Daivuk]

I've merged didn't try it, I trust this is good. But I'm a little confused as to why this is an issue in the first place. This is original DOOM code. Aligning it like that will make allocation need bigger. Doesn't DOOM allocate fixed amount at the start? Then we end up with less memory. Did you play the full game to make sure this works?

[Mellurboo]

Did you play the full game to make sure this works?

playing the full game isnt possible as it infact Segmentation Faults at init, it points to doom_strcpy. this was tested on 4 machines

[korbykob]

Yeah, I've been using this awesome project to port doom quick and easily, however I've had issues with memory alignment, I assume this would also just make things faster as aligned memory is atomic to read and write to, this does work fine from what I've tested with my own OS and other OSes too.