Add --with-postgresql option to configure.ac.
Add --with-postgresql option to configure.ac.

- './configure --with-postgresql' will enable building with
  experimental PostgreSQL support.  Default is not to enable
  PostgreSQL support.

lees0414/EUproject,alco90/soml,mytestbed/oml,alco90/soml,alco90/soml,lees0414/EUproject,mytestbed/oml,lees0414/EUproject,lees0414/EUproject,alco90/soml,alco90/soml,mytestbed/oml,mytestbed/oml,lees0414/EUproject,mytestbed/oml