netinet/ip - Avoid a NULL pointer dereference.

- Before checking for packets on broadcast addresses, see if there
  is actually a ifnet associated with the mbuf being handled.

FreeBSD-SVN: 130685
DragonFly-bug: <http://bugs.dragonflybsd.org/issues/2660>
Reported-and-Found-by: Vasily Postnicov

This commit closes #2660
Remove the acpisrc utility which is for ACPICA distribution maintenance.

This is not necessary in base. In the unlikely case that anyone ever
needed it, we can bring it back.