--- boost_1_49_0/boost/property_tree/detail/json_parser_read.hpp	2012-06-19 16:45:16.881735127 -0300
+++ boost_minimal/boost/property_tree/detail/json_parser_read.hpp	2012-06-19 16:45:20.777804293 -0300
@@ -112,7 +112,7 @@
         {
             context &c;
             a_char(context &c): c(c) { }
-            void operator()(It b, It e) const
+            void operator()(It b, It /* e */) const
             {
                 c.string += *b;
             }