BUG: Command should be inherited.

Source/cmStringCommand.h

@@ -41,6 +41,12 @@ public:
    */
   virtual bool InitialPass(std::vector<std::string> const& args);
 
+  /**
+   * This determines if the command gets propagated down
+   * to makefiles located in subdirectories.
+   */
+  virtual bool IsInherited() {return true;}
+
   /**
    * The name of the command as specified in CMakeList.txt.
    */