CREATE OR REPLACE FUNCTION last_sfunc(anyelement, anyelement)
RETURNS anyelement
AS '$libdir/first_last_agg', 'last_sfunc'
LANGUAGE C IMMUTABLE STRICT;

CREATE OR REPLACE FUNCTION first_sfunc(anyelement, anyelement)
RETURNS anyelement
AS '$libdir/first_last_agg', 'first_sfunc'
LANGUAGE C IMMUTABLE STRICT;