alignment requirement, while rt_msghdr has a 4 byte alignment
requirement. The root cause is that if_msghdr has an struct if_data
which has an 8-byte alignment requirement due to a time_t that's
embedded in it. On MIPS, time_t is a 64-bit number, so must be 64-bit
aligned.
Since we don't access ifm_data.ifi_epoch, a simple cast is all that's
necessary here. It is likely the case that ifi_epoch should *NOT* be
a time_t because it is an uptime (time delta) an not an absolute time
since 1970. u_long is likely sufficient there since that gives an
uptime of 136 years will suffice for the foreseeable future.