do not show message box in headless mode

diff --git a/src/game/g_main.pas b/src/game/g_main.pas
index 16085cead25ca40398edda2a2a43bb8a4b6f51e6..94606737be95baed9247cbfe82d29f4ca792af2a 100644 (file)
--- a/src/game/g_main.pas
+++ b/src/game/g_main.pas
@@ -367,7 +367,7 @@ begin
   if GameWad = '' then
   begin
     e_WriteLog('GAME.WAD not installed?', TMsgType.Fatal);
-    {$IFDEF USE_SDL2}
+    {$IF DEFINED(USE_SDL2) AND NOT DEFINED(HEADLESS)}
       SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, 'Doom 2D Forever', 'GAME.WAD not installed?', nil);
     {$ENDIF}
     Halt(1);