Compile Sqlite with RTree support.

GDAL requires this feature.

component/sqlite3/buildout.cfg

@@ -24,6 +24,6 @@ post-install =
 # https://git.archlinux.org/svntogit/packages.git/tree/trunk/PKGBUILD?h=packages/sqlite
 # NEO needs SQLITE_ENABLE_UPDATE_DELETE_LIMIT to drop partitions.
 environment =
-  CPPFLAGS=-I${zlib:location}/include -DSQLITE_MAX_VARIABLE_NUMBER=250000
+  CPPFLAGS=-I${zlib:location}/include -DSQLITE_MAX_VARIABLE_NUMBER=250000 -DSQLITE_ENABLE_RTREE=1
   LDFLAGS=-Wl,-rpath=@@LOCATION@@/lib -L${readline:location}/lib -Wl,-rpath=${readline:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib
   PATH=${tcl:location}/bin:${xz-utils:location}/bin:%(PATH)s