In sbin/swapctl
    swapctl.o: Undefined symbol 'SYS_swapctl' referenced from text segment.
   (This is very annoying, I couldn't get a swap.)

you didn't 'make includes'.  your old swapon(8) program should continue
to work if you include COMPAT_12 in your kernel configuration.
   
   In usr.bin/dhcp/common
    make: don't know how to make dns.c.

dunno about this one.