anchor.diff:  considered part of its parent's scope; if it is indented less than the
   previous one, it closes the previous scope.
   
  +[[ref_toplevel]]
   Top-level variables
   ~~~~~~~~~~~~~~~~~~~
   
  
positive.code: come up yet so it's difficult to predict what behavior might be
  required.
  
  
  Ninja file reference
  --------------------
  
negative.code: 
  `depfile`:: path to an optional `Makefile` that contains extra
    _implicit dependencies_ (see <<ref_dependencies,the reference on
    dependency types>>).  This is explicitly to support C/C++ header
    dependencies; see <<ref_headers,the full discussion>>.
  
  `deps`:: _(Available since Ninja 1.3.)_ if present, must be one of
    `gcc` or `msvc` to specify special dependency processing.  See
     <<ref_headers,the full discussion>>.  The generated database is
     stored as `.ninja_deps` in the `builddir`, see <<ref_toplevel,the
     discussion of `builddir`>>.
  
  `description`:: a short description of the command, used to pretty-print
    the command as it's running.  The `-v` flag controls whether to print
  