+ Make destructor virtual for classes with virtual methods (based on DevJohan's patch)

src/Mod/Mesh/App/Core/Algorithm.h

@@ -318,6 +318,7 @@ class MeshExport MeshCollector
 {
 public:
     MeshCollector(){}
+    virtual ~MeshCollector(){}
     virtual void Append(const MeshCore::MeshKernel&, unsigned long index) = 0;
 };
 
@@ -325,6 +326,7 @@ class MeshExport PointCollector : public MeshCollector
 {
 public:
     PointCollector(std::vector<unsigned long>& ind) : indices(ind){}
+    virtual ~PointCollector(){}
     virtual void Append(const MeshCore::MeshKernel& kernel, unsigned long index)
     {
         unsigned long ulP1, ulP2, ulP3;
@@ -342,6 +344,7 @@ class MeshExport FacetCollector : public MeshCollector
 {
 public:
     FacetCollector(std::vector<unsigned long>& ind) : indices(ind){}
+    virtual ~FacetCollector(){}
     void Append(const MeshCore::MeshKernel&, unsigned long index)
     {
         indices.push_back(index);

src/Mod/Mesh/App/Mesh.h

@@ -82,7 +82,7 @@ public:
     explicit MeshObject(const MeshCore::MeshKernel& Kernel);
     explicit MeshObject(const MeshCore::MeshKernel& Kernel, const Base::Matrix4D &Mtrx);
     MeshObject(const MeshObject&);
-    ~MeshObject();
+    virtual ~MeshObject();
 
     void operator = (const MeshObject&);
 

src/Mod/Sketcher/App/Constraint.h

@@ -56,9 +56,9 @@ class SketcherExport Constraint : public Base::Persistence
     TYPESYSTEM_HEADER();
 
 public:
-    ~Constraint();
     Constraint();
     Constraint(const Constraint&);
+    virtual ~Constraint();
     virtual Constraint *clone(void) const;
 
     static const int GeoUndef;

src/Mod/Sketcher/App/freegcs/Constraints.h

@@ -58,6 +58,7 @@ namespace GCS
         int tag;
     public:
         Constraint();
+        virtual ~Constraint(){}
 
         inline VEC_pD params() { return pvec; }