gazetteer: ignore landuse without name

also fixes a tiny memory leak with landuses
make clean should delete files generated by protobuf
Fork not supported on MinGW.
Added additional logic to properly detect mingw. More udpates for supporting custom protobuf-c paths. Mthread support detection updates.
MinGW also requires GEOS_INLINE.
Updates to support custom protobuf-c paths on mingw. Old logic was self sabotaging itself by resetting includes to nothing when the inc/lib specific flags were specified to configure.
Not sure why __MINGW_H macro is used. __MINGW32__ or __MINGW__ are the standard widely used macros. I couldn't get osm2psql to build with the _H macro. I went forward using _MINGW32__, which is what you see in most open source ports to this platform.
Moved config.h header down the headers list so the VERSION and PACKAGE_VERSION macros wouldn't interfere with osm2pgsqls.
Revert pthread updates.
Make sure any protobuf-c dependencies are included after.
removed extra bracket on cygwin macro.
added mingw package script.