Put WARNING in PostGIS missing functionality if
|Reported by:||robe||Owned by:||pramsey|
If someone happens to compile PostGIS without certain libraries/versions even though we allow it e.g. GDAL 1.7+, GEOS 3.3+
We should put in a big warning that they will be missing functionality.
Maybe with a URL to our matrix of reasons. Still need to put in GDAL dependency in matrix. LibXML I didn't bother since can't compile without it and we aren't using any functionality found in newer versions.