Enclosed below I have a patch to allow a btree index on the int8 type.

I would like some feedback on what the hash function for the int8 hash
function
in the ./backend/access/hash/hashfunc.c should return.

Also, could someone (maybe Tomas Lockhart?) look-over the patch and make
sure
the system table entries are correct?  I've tried to research them as
much as I
could, but some of them are still not clear to me.

Thanks,
-Ryan