Prevent the kernel from generating an unaligned sysctl data buffer on
64-bit platforms. The unaligned access is caused by struct ifa_msghdr
not being a multiple of 8-bytes in size. If an interface has an odd
number of addresses, this causes the next interface to generate an
unaligned access in the user-level app walking the interfaces (ifconfig).

Submitted by: Bernd Walter <ticso@cicely8.cicely.de>