guile-sdl: fix after multiple-outputs change

pkgs/development/guile-modules/guile-sdl/default.nix

···
   nativeBuildInputs = [ guile ];
 
   buildInputs = [
-    SDL SDL_image SDL_ttf SDL_mixer
+    SDL.dev SDL_image SDL_ttf SDL_mixer
   ];
 
   GUILE_AUTO_COMPILE = 0;