Currently, the second argument of getlogin(2), gethostname(2),
sethostname(2), getdomainname(2), and setdomainname(2) are `u_int's,
the second argument of msync(2), munmap(2), mprotect(2), madvise(2),
and mincore(2) are `int's.  In addition, all of the syscalls that use
sockaddr lengths use `int' or `int *'.

I want to change all of these to use `size_t' rather than `int' or
`u_int'.  I think this should be backward compatible in all cases,
except possibly on the Alpha.

Are there any reasons I shouldn't do this?