I wanted to add the static plugin functionality to cmake, too. But https://github.com/mapnik/mapnik/blob/master/src/datasource_cache_static.cpp declares either plugins, which are not present anymore or currently available plugins not.

Missing plugin definitions: geobuf, pgraster, topojson

So my question is: Is this feature deprecated/not used by anyone or should it be maintained? (add missing definitions)

There are also double declared symbols when using ogr and gdal as a static plugin (on_plugin_load)