added null graphics driver (USE_NULL_DRIVER)

will make it nicer later.

svn-id: r3931

1 files changed, 2 insertions, 0 deletions

diff --git a/system.h b/system.h
index b2afb8eb19..69f4a9ee49 100644
--- a/system.h
+++ b/system.h
@@ -102,6 +102,7 @@ public:
 
 /* OSystem_SDL */
 OSystem *OSystem_SDL_create(int gfx_driver, bool full_screen);
+OSystem *OSystem_NULL_create();
 
 enum {
 	GFX_NORMAL = 0,
@@ -119,6 +120,7 @@ enum {
 	GD_SDL = 1,
 	GD_WIN32 = 2,
 	GD_X = 3,
+	GD_NULL = 4,
 };