Add missing ignore of osm_timestamp in tagtransform_c_filter_rel_member_tags()

When reading a .osm or .o5m instead of .osm.pbf file, this caused osm2pgsql to
generate ways included in relations in planet_osm_polygons in addition to the
relation.
Get changeset attribute from .osm file, to align with .osm.pbf
Merge pull request #136 from jocelynj/osm-fixes

Unwanted way in planet_osm_polygon with test .osm
fix header guard typos and add missing ones
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.