Fix -Wundef warnings due to use of unguarded SDL_VIDEO_DRIVER_NGAGE

src/video/SDL_video.c

@@ -121,7 +121,7 @@ static VideoBootStrap *bootstrap[] = {
 #if SDL_VIDEO_DRIVER_OFFSCREEN
     &OFFSCREEN_bootstrap,
 #endif
-#if SDL_VIDEO_DRIVER_NGAGE
+#ifdef SDL_VIDEO_DRIVER_NGAGE
     &NGAGE_bootstrap,
 #endif
 #if SDL_VIDEO_DRIVER_DUMMY

src/video/ngage/SDL_ngageevents.cpp

@@ -21,7 +21,7 @@
 
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_DRIVER_NGAGE
+#ifdef SDL_VIDEO_DRIVER_NGAGE
 
 /* Being a ngage driver, there's no event stream. We just define stubs for
    most of the API. */

src/video/ngage/SDL_ngageframebuffer.cpp

@@ -21,7 +21,7 @@
 
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_DRIVER_NGAGE
+#ifdef SDL_VIDEO_DRIVER_NGAGE
 
 #include <SDL.h>
 

src/video/ngage/SDL_ngagevideo.cpp

@@ -25,7 +25,7 @@
 #endif
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_DRIVER_NGAGE
+#ifdef SDL_VIDEO_DRIVER_NGAGE
 
 #ifdef __cplusplus
 extern "C" {

src/video/ngage/SDL_ngagewindow.cpp

@@ -21,7 +21,7 @@
 
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_DRIVER_NGAGE
+#ifdef SDL_VIDEO_DRIVER_NGAGE
 
 #include "../SDL_sysvideo.h"