COMPAT_43 and COMPAT_DF12 gone

Well, they’re still available, but you don’t want them in your config any more because they can slow you down.  This will only affect you if you are running binary files from DragonFly 1.2 or earlier, or…  I guess a 4.3 BSD binary?  From 1986?  I’m sure there’s some other reason for it to be there.