anchor.diff:  
   local function exec(cmd)
   	--print(cmd)
  -	local status = os.execute(cmd)
  +	local status = os.execute("type NUL && "..cmd)
   	return (status == 0 or status == true) -- compat 5.1/5.2
   end
   
  
positive.code: vars.PREFIX = nil
  vars.VERSION = "2.2"
  vars.SYSCONFDIR = nil
  vars.SYSCONFFILENAME = nil
  vars.CONFIG_FILE = nil
  vars.TREE_ROOT = nil
  
negative.code: -- ***********************************************************
  -- Install LuaRocks files
  -- ***********************************************************
  
  if exists(vars.FULL_PREFIX) then
    if not FORCE then
      die(S"$FULL_PREFIX exists. Use /F to force removal and reinstallation.")
    else
      backup_config_files()
      print(S"Removing $FULL_PREFIX...")
      exec(S[[RD /S /Q "$FULL_PREFIX"]])
      print()
    end
  end
  
  print(S"Installing LuaRocks in $FULL_PREFIX...")
  