anchor.diff:  ninja input files.  Ninja by itself is unlikely to be useful for most
   projects.
   
  -Here are some of the features Ninja adds to make.  (These sorts of
  +Here are some of the features Ninja adds to Make.  (These sorts of
   features can often be implemented using more complicated Makefiles,
   but they are not part of make itself.)
   
  
positive.code: 
  ----
  rule demo
    command = echo "this is a demo of $foo'
  
  build out: demo
    foo = bar
  
negative.code: Comparison to Make
  ~~~~~~~~~~~~~~~~~~
  
  Ninja is closest in spirit and functionality to Make, relying on
  simple dependencies between file timestamps.
  
  But fundamentally, make has a lot of _features_: suffix rules,
  