Drop liblwgeom_internal.h use from postgis_topology module
|Reported by:||strk||Owned by:||strk|
This is propedeutic to giving liblwgeom his own release cycles.
Internal API is currently only needed for cloning a gbox, which is something that could very well be in the public API:
postgis_topology.c:#include "liblwgeom_internal.h" /* for gbox_clone */