destructors should be virtual to be processed in the correct order

src/XTC/dump_xtc.h

@@ -34,7 +34,7 @@ namespace LAMMPS_NS {
 class DumpXTC : public Dump {
  public:
   DumpXTC(class LAMMPS *, int, char**);
-  ~DumpXTC();
+  virtual ~DumpXTC();
 
  private:
   int natoms,ntotal;

src/dump_cfg.h

@@ -27,7 +27,7 @@ namespace LAMMPS_NS {
 class DumpCFG : public DumpCustom {
  public:
   DumpCFG(class LAMMPS *, int, char **);
-  ~DumpCFG();
+  virtual ~DumpCFG();
 
  private:
   char **auxname;            // name strings of auxiliary properties

src/dump_dcd.h

@@ -27,7 +27,7 @@ namespace LAMMPS_NS {
 class DumpDCD : public Dump {
  public:
   DumpDCD(LAMMPS *, int, char**);
-  ~DumpDCD();
+  virtual ~DumpDCD();
 
  private:
   int natoms,ntotal;

src/dump_local.h

@@ -27,7 +27,7 @@ namespace LAMMPS_NS {
 class DumpLocal : public Dump {
  public:
   DumpLocal(LAMMPS *, int, char **);
-  ~DumpLocal();
+  virtual ~DumpLocal();
 
  private:
   int nevery;                // dump frequency to check Fix against

src/dump_xyz.h

@@ -27,7 +27,7 @@ namespace LAMMPS_NS {
 class DumpXYZ : public Dump {
  public:
   DumpXYZ(class LAMMPS *, int, char**);
-  ~DumpXYZ();
+  virtual ~DumpXYZ();
 
  private:
   void init_style();