Make nlink_t 32bit and ino_t 64bit. Implement the old syscall numbers

Make nlink_t 32bit and ino_t 64bit. Implement the old syscall numbers
for *stat by wrapping the new syscalls and truncation of the values.
Add a hack for boot2 to keep ino_t 32bit, otherwise we would have to
link the 64bit math code in and that would most likely overflow boot2.
Bump libc major to annotate changed ABI and work around a problem with
strip during installworld. strip is dynamically linked and doesn't play
well with the new libc otherwise.

Support for 64bit inode numbers is still incomplete, because the dirent
limited to 32bit. The checks for nlink_t have to be redone too.