In order to build this extension yourself you need the db++ client libraries
and header files to be installed on your system (these are included in the
db++ installation archives by default). You have to run
configure with option --with-dbplus to
build this extension.
configure looks for the client libraries and header files
under the default paths /usr/dbplus,
/usr/local/dbplus and /opt/dblus.
If you have installed db++ in a different place you have add the installation
path to the configure option like this:
--with-dbplus=/your/installation/path.