Fix the build with GCC4.8

Signed-off-by: Jérôme Duval <[email protected]>

headers/libs/agg/agg_conv_curve.h

@@ -154,10 +154,10 @@ namespace agg
             return path_cmd_line_to;
         }
 
-        double ct2_x;
-        double ct2_y;
-        double end_x;
-        double end_y;
+        double ct2_x = 0;
+        double ct2_y = 0;
+        double end_x = 0;
+        double end_y = 0;
 
         unsigned cmd = m_source->vertex(x, y);
         switch(cmd)

headers/libs/agg/agg_rasterizer_scanline_aa.h

@@ -187,8 +187,8 @@ namespace agg
         template<class VertexSource>
         void add_path(VertexSource& vs, unsigned path_id=0)
         {
-            double x;
-            double y;
+            double x = 0;
+            double y = 0;
 
             unsigned cmd;
             vs.rewind(path_id);