ENH: Add a depends check step to custom targets. Add support for the IMPLICIT_DEPENDS feature of custom commands when building in custom targets. Convert multiple-output pair checks to be per-target instead of global.

Source/cmLocalUnixMakefileGenerator3.h

@@ -203,9 +203,6 @@ public:
   virtual bool UpdateDependencies(const char* tgtInfo,
                                   bool verbose, bool color);
 
-  /** Called from command-line hook to scan dependencies.  */
-  bool ScanDependencies(const char* tgtInfo);
-
   /** Called from command-line hook to clear dependencies.  */
   virtual void ClearDependencies(cmMakefile* mf, bool verbose);
   
@@ -325,6 +322,10 @@ protected:
 
   std::map<cmStdString, std::vector<int> > ProgressFiles;
 
+  // Helper methods for dependeny updates.
+  bool ScanDependencies(const char* targetDir);
+  void CheckMultipleOutputs(bool verbose);
+
 private:
   friend class cmMakefileTargetGenerator;
   friend class cmMakefileExecutableTargetGenerator;