Remove SDL_config.h from the public headers

The SDL headers are no longer dependent on the build configuration.

Fixes https://github.com/libsdl-org/SDL/issues/6643 and https://github.com/libsdl-org/SDL/issues/6641

src/dynapi/SDL_dynapi.c

@@ -19,11 +19,15 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#include "SDL_config.h"
+#include "build_config/SDL_build_config.h"
 #include "SDL_dynapi.h"
 
 #if SDL_DYNAMIC_API
 
+#ifdef HAVE_STDIO_H
+#include <stdio.h>
+#endif
+
 #include "SDL.h"
 
 /* These headers have system specific definitions, so aren't included above */