Only define BSD if not already defined
Only define BSD if not already defined

This is a workaround for https://github.com/mozy/mordor/issues/13. I
really need to move to using autoconf's macros, rather than these
primitive OS checks.

adfin/mordor,adfin/mordor,ccutrer/mordor,ccutrer/mordor,ccutrer/mordor,mtanski/mordor,adfin/mordor,mtanski/mordor,mtanski/mordor