Fix copying of text_symbolizer_properties in one place.

Needs a more general solution.
Refs #1780.

src/text/placements/base.cpp

@@ -19,9 +19,14 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  *
  *****************************************************************************/
+// mapnik
 #include <mapnik/text/placements/base.hpp>
 
+// boost
+#include <boost/make_shared.hpp>
+
 namespace mapnik {
+
 text_placements::text_placements() : defaults()
 {
 }
@@ -39,7 +44,7 @@ text_placement_info::text_placement_info(text_placements const* parent,
     : properties(parent->defaults),
       scale_factor(scale_factor_)
 {
-
+    properties.format = boost::make_shared<char_properties>(*(properties.format));
 }
 
 } //ns mapnik