Replace the 4.3BSD getdirentries compat function with something which is

Replace the 4.3BSD getdirentries compat function with something which is
much more likely to work. The old dirent is basically the on-disk format
of UFS, so the reordering done for little endian machines in ufs_readdir
is reverted here, which should also catch the native order of all other
filesystem. I'm not 100% sure if this change is correct, but the old
code was broken at best, so it shouldn't make matters worse.