anchor.diff:    vars.CONFBACKUPDIR = temppath
     mkdir(vars.CONFBACKUPDIR)
     exec(S[[COPY "$PREFIX\config*.*" "$CONFBACKUPDIR" >NUL]])
  -  exec(S[[COPY "$PREFIX\lua\luarocks\core\site_config*.*" "$CONFBACKUPDIR" >NUL]])
   end
   
   -- restore previously backed up config files
   local function restore_config_files()
     if not vars.CONFBACKUPDIR then return end -- there is no backup to restore
     exec(S[[COPY "$CONFBACKUPDIR\config*.*" "$PREFIX" >NUL]])
  -  exec(S[[COPY "$CONFBACKUPDIR\site_config*.*" "$PREFIX\lua\luarocks\core" >NUL]])
     -- cleanup
     exec(S[[RD /S /Q "$CONFBACKUPDIR"]])
     vars.CONFBACKUPDIR = nil
  
positive.code: 	return false
  end
  
  -- backup config[x.x].lua[.bak] and site_config[_x_x].lua
  local function backup_config_files()
    local temppath
    while not temppath do
  
negative.code: rem=rem --[[--lua
  @setlocal&  set luafile="%~f0" & if exist "%~f0.bat" set luafile="%~f0.bat"
  @win32\lua5.1\bin\lua5.1.exe %luafile% %*&  exit /b ]]
  
  