added destructor to loaded commands

Source/cmCPluginAPI.h

@@ -176,6 +176,7 @@ Finally we define the key data structures and function prototypes
   typedef int (*CM_INITIAL_PASS_FUNCTION)(void *info, void *mf, 
                                           int argc, char *[]);
   typedef void (*CM_FINAL_PASS_FUNCTION)(void *info, void *mf);
+  typedef void (*CM_DESTRUCTOR_FUNCTION)(void *info);
   
   typedef struct {
     unsigned char magic1;
@@ -184,6 +185,7 @@ Finally we define the key data structures and function prototypes
     int m_Inherited;
     CM_INITIAL_PASS_FUNCTION InitialPass;
     CM_FINAL_PASS_FUNCTION FinalPass;
+    CM_DESTRUCTOR_FUNCTION Destructor;
     CM_DOC_FUNCTION GetTerseDocumentation;
     CM_DOC_FUNCTION GetFullDocumentation;  
     void *ClientData;

Source/cmLoadCommandCommand.cxx

@@ -28,6 +28,9 @@ public:
     this->info.CAPI = &cmStaticCAPI;
   }
   
+  ///! clean up any memory allocated by the plugin
+  ~cmLoadedCommand();
+    
   /**
    * This is a virtual constructor for the command.
    */
@@ -139,7 +142,14 @@ void cmLoadedCommand::FinalPass()
     {
     this->info.FinalPass((void *)&this->info,(void *)this->m_Makefile);
     }
-  
+}
+
+cmLoadedCommand::~cmLoadedCommand()
+{
+  if (this->info.Destructor)
+    {
+    this->info.Destructor((void *)&this->info);
+    }
 }
 
 // cmLoadCommandCommand