Fix -Wundef warnings due to use of unguarded SDL_VIDEO_RENDER_METAL

src/render/SDL_render.c

@@ -98,7 +98,7 @@ static const SDL_RenderDriver *render_drivers[] = {
 #ifdef SDL_VIDEO_RENDER_D3D
     &D3D_RenderDriver,
 #endif
-#if SDL_VIDEO_RENDER_METAL
+#ifdef SDL_VIDEO_RENDER_METAL
     &METAL_RenderDriver,
 #endif
 #if SDL_VIDEO_RENDER_OGL

src/render/metal/SDL_render_metal.m

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_METAL && !defined(SDL_RENDER_DISABLED)
+#if defined(SDL_VIDEO_RENDER_METAL) && !defined(SDL_RENDER_DISABLED)
 
 #include "../SDL_sysrender.h"