anchor.diff:  build myapp.exe: link a.obj b.obj [possibly many other .obj files]
   ----
   
  -Finally, the special `$in` and `$out` variables expand to the
  -shell-quoted space-separated list of files provided to the `build`
  -line referencing this `rule`.
  -
   [[ref_dependencies]]
   Build dependencies
   ~~~~~~~~~~~~~~~~~~
  
positive.code: follows an indented set of `variable = value` lines.
  
  The basic example above declares a new rule named `cc`, along with the
  command to run.  (In the context of a rule, the `command` variable is
  special and defines the command to run.  A full list of special
  variables is provided in <<ref_rule,the reference>>.)
  
  Within the context of a rule, three additional special variables are
  available: `$in` expands to the list of input files (`foo.c`) and
  `$out` to the output file (`foo.o`) for the command. For use with
  `$rspfile_content`, there is also `$in_newline`, which is the same as
  `$in`, except that multiple inputs are separated by `\n`, rather than
  spaces.
  
  
  Build statements
  ~~~~~~~~~~~~~~~~
  
negative.code:   rebuilt if the command line changes; and secondly, they are not
    cleaned by default.
  
  `in`:: the shell-quoted space-separated list of files provided as
    inputs to the build line referencing this `rule`.  (`$in` is provided
    solely for convenience; if you need some subset or variant of this
    list of files, just construct a new variable with that list and use
    that instead.)
  
  `in_newline`:: the same as `$in` except that multiple inputs are
    separated by newlines rather than spaces.  (For use with
    `$rspfile_content`; this works around a bug in the MSVC linker where
    it uses a fixed-size buffer for processing input.)
  
  `out`:: the shell-quoted space-separated list of files provided as
    outputs to the build line referencing this `rule`.
  
  `restat`:: if present, causes Ninja to re-stat the command's outputs
    after execution of the command.  Each output whose modification time
    the command did not change will be treated as though it had never
  