From Kristofer Tingdahl, Build fix for svg plugin that makes sure the version of librsvg is at sufficient, and fixed a missing virtual destructor warning.

CMakeModules/FindRSVG.cmake

@@ -5,7 +5,9 @@ IF(PKG_CONFIG_FOUND)
 
     INCLUDE(FindPkgConfig)
 
-    PKG_CHECK_MODULES(RSVG librsvg-2.0)
+    #Version 2.35 introduces the rsvg_cleanup function which is used
+    PKG_CHECK_MODULES(RSVG librsvg-2.0>=2.35)
+
     PKG_CHECK_MODULES(CAIRO cairo)
 
     IF (RSVG_FOUND AND NOT CAIRO_FOUND)

include/osg/ValueObject

@@ -44,6 +44,7 @@ class ValueObject : public Object
         class GetValueVisitor
         {
         public:
+            virtual ~GetValueVisitor() {}
             virtual void apply(bool /*value*/) {}
             virtual void apply(char /*value*/) {}
             virtual void apply(unsigned char /*value*/) {}
@@ -69,6 +70,7 @@ class ValueObject : public Object
         class SetValueVisitor
         {
         public:
+            virtual ~SetValueVisitor() {}
             virtual void apply(bool& /*value*/) {}
             virtual void apply(char& /*value*/) {}
             virtual void apply(unsigned char& /*value*/) {}