comp_short_keys() massaged into sane form, which kills the last place where
pointer to in_core_key (or any object containing such) would be cast to or
from something else.  At that point we are free to change layout of
in_core_key - nothing depends on it anymore.

So we drop the mess with union in there and simply use (unconditional) __u64
k_offset and __u8 k_type instead; places using in_core_key switched to those.
That gives _far_ better code than current mess - on all platforms.
Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Cc: <reiserfs-dev@namesys.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>