Log Message:-----------Document PGXS' REGRESS feature.
Modified Files:-------------- pgsql/doc/src/sgml: xfunc.sgml (r1.108 -> r1.109) (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xfunc.sgml.diff?r1=1.108&r2=1.109)