anchor.diff:  as progress status and output from concurrent tasks) is buffered until
   it completes.
   
  +[[ref_ninja_file]]
   Ninja file reference
   --------------------
   
  
positive.code:   the command as it's running.  The `-v` flag controls whether to print
    the full command or its description; if a command fails, the full command
    line will always be printed before the command's output.
  
  `generator`:: if present, specifies that this rule is used to
    re-invoke the generator program.  Files built using `generator`
  
negative.code: 6. A pool declaration, which looks like +pool _poolname_+. Pools are explained
     <<ref_pool, in the section on pools>>.
  
  [[ref_lexer]]
  Lexical syntax
  ~~~~~~~~~~~~~~
  
  