include/mapnik/timer.hpp:59:13: error: member function 'stop' not viable: 'this' argument has type 'const mapnik::timer', but function
      is not marked const
            stop();
            ^~~~
include/mapnik/timer.hpp:49:18: note: 'stop' declared here
    virtual void stop()
                 ^
include/mapnik/timer.hpp:68:13: error: member function 'stop' not viable: 'this' argument has type 'const mapnik::timer', but function
      is not marked const
            stop();
            ^~~~
include/mapnik/timer.hpp:49:18: note: 'stop' declared here
    virtual void stop()
                 ^
include/mapnik/timer.hpp:104:78: error: expected ';' after expression
            s << wall_clock_elapsed() << "ms (cpu " << cpu_elapsed() << "ms)"
                                                                             ^
                                                                             ;
3 errors generated.