anchor.diff:  :pwad_master
   REM --------------------------------------------------------------------------------------------------------------------
   REM # are we looking for "Master Levels for DOOM II"?
  -IF NOT /I "%PWAD:~0,7%" == "MASTER\" GOTO :pwad_missing
  +IF /I NOT "%PWAD:~0,7%" == "MASTER\" GOTO :pwad_missing
   
   REM # extract the WAD name from that
   SET "WAD=%PWAD:~8%"
  
positive.code: PAUSE
  EXIT /B 1
  
  :iwad_freedom
  REM # if this was DOOM or DOOM2, we could use FreeDOOM instead
  SET "FREEDOOM="
  REM # TODO: check these files exist too
  
negative.code: :iwad_doom2
  REM --------------------------------------------------------------------------------------------------------------------
  REM # are we looking for "DOOM II"?
  IF /I NOT "%IWAD%" == "DOOM2.WAD" GOTO :iwad_tnt
  
  REM # is Steam : DOOM II installed?
  CALL :reg "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 2300" "InstallLocation"
  