Fix -Wundef warnings due to use of unguarded SDL_VIDEO_RENDER_PS2

src/render/SDL_render.c

@@ -107,7 +107,7 @@ static const SDL_RenderDriver *render_drivers[] = {
 #if SDL_VIDEO_RENDER_OGL_ES2
     &GLES2_RenderDriver,
 #endif
-#if SDL_VIDEO_RENDER_PS2
+#ifdef SDL_VIDEO_RENDER_PS2
     &PS2_RenderDriver,
 #endif
 #if SDL_VIDEO_RENDER_PSP

src/render/ps2/SDL_render_ps2.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_PS2
+#ifdef SDL_VIDEO_RENDER_PS2
 
 #include "../SDL_sysrender.h"