Do *not* force directx mode. I don't like it.

If you want hardware scaling on Windows in overlay mode, set
SDL_VIDEODRIVER=directx before running it.

src/conio/SDL_win32_main.c

@@ -200,10 +200,6 @@ int console_main(int argc, char *argv[], char **env)
 	int n;
 	char *bufp, *appname;
 
-	if(getenv("SDL_VIDEODRIVER")==NULL) {
-		putenv("SDL_VIDEODRIVER=directx");
-	}
-
 	/* Get the class name from argv[0] */
 	appname = argv[0];
 	if ( (bufp=strrchr(argv[0], '\\')) != NULL ) {