ENH: add GetCleanTargetName() which returns "clean" for makefiles, so it can

be used by the eclipse generator

Alex

Source/cmGlobalGenerator.h

@@ -224,6 +224,7 @@ public:
   virtual const char* GetPackageSourceTargetName(){ return 0; }
   virtual const char* GetEditCacheTargetName()    { return 0; }
   virtual const char* GetRebuildCacheTargetName() { return 0; }
+  virtual const char* GetCleanTargetName()        { return 0; }
 
   // what targets does the specified target depend on
   std::vector<cmTarget *>& GetTargetDepends(cmTarget& target);

Source/cmGlobalUnixMakefileGenerator3.h

@@ -177,6 +177,7 @@ protected:
   virtual const char* GetPackageSourceTargetName(){ return "package_source"; }
   virtual const char* GetEditCacheTargetName()    { return "edit_cache"; }
   virtual const char* GetRebuildCacheTargetName() { return "rebuild_cache"; }
+  virtual const char* GetCleanTargetName()        { return "clean"; }
 
   // Some make programs (Borland) do not keep a rule if there are no
   // dependencies or commands.  This is a problem for creating rules