Guest builds (DragonFly 6.5-DEVELOPMENT, /usr/src):
  tools:   cc -O2 -o /root/{icmp_oob,kcheck,kslots,ktree,kpeek,kscan,kprobe,query_nat,icmp_in} ...
  baseline module: cd /usr/src/sys/net/ipfw3_nat && make && make install   (pristine source)
  fixed module:    same, after `patch -p1 < fix.diff`
  kernel:          cd /usr/src && make -j6 nativekernel  (RC=0) ; make -j6 installkernel (RC=0)
                   -> DragonFly 6.5-DEVELOPMENT #1 (identical source except the module fix)
All builds exited 0; no warnings on the touched files.