Fixed compilation on Mac OS 10.8 / Mountain Lion

libs/lib/mac64/include/osgDB/Serializer

@@ -47,7 +47,7 @@ public:
         if ( _valueToString.find(value)!=_valueToString.end() )
         {
             osg::notify(osg::WARN) << "Duplicate enum value " << value
-                                   << " with old string: " << _valueToString[value]
+                                   << " with old string: " << _valueToString[value].c_str()
                                    << " and new string: " << str << std::endl;
         }
         _valueToString[value] = str;

src/ui/map3D/Imagery.cc

@@ -614,7 +614,7 @@ Imagery::getTileLocation(int tileX, int tileY, int zoomLevel,
             << "&y=" << tileY << "&z=" << zoomLevel;
         break;
     case OFFLINE_SATELLITE:
-        oss << mImageryPath << "/200/color/" << tileY
+        oss << mImageryPath.c_str() << "/200/color/" << tileY
             << "/tile-";
         if (tileResolution < 1.0)
         {