ENH: Keep only FinalPass commands in memory

In cmMakefile we save all invoked commands so that FinalPass can be
called on them later.  Most commands have no final pass, so we should
keep only the few that do.

Source/cmConfigureFileCommand.h

@@ -81,6 +81,7 @@ public:
     }
 
   virtual void FinalPass();
+  virtual bool HasFinalPass() const { return !this->Immediate; }
 private:
   int ConfigureFile();