Added -std=c++1z to the "Generate dependencies" example; sometimes more advanced code needs this.

Makefile

@@ -288,7 +288,7 @@ help:
 #
 # THE COMPILER CAN GENERATE DEPENDENCIES FROM SOURCE CODE
 #
-# % g++ -MM *.cpp
+# % g++ -std=c++1z -MM *.cpp
 #
 # ADD YOUR OWN DEPENDENCIES HERE