ioctl commands such as BIOCSETIF take a struct ifreq and due to
FreeBSD's ioctl implementation copy exactly sizeof(struct ifreq) bytes
in so allocate exactly that much space.
The over-allocaton was harmless, but useless.
Reported by: def
Fixes: e2dc8d789f68a dhclient: do not add 0.0.0.0 interface alias.
Sponsored by: DARPA, AFRL