Add makefile.unix definitions (tested on glibc, not sure if *bsd libc support these options) to allow debug.log to grow past 2GB on 32bit builds.
I ran into this problem when I noticed that debug.log stops updating at 2GB on my 32bit host.
This will also make it so that the block chain can grow past 2GB on 32bit builds.
We may need some further options for *bsd's libc but I don't have available test installs at the moment.